Ridetheducksofseattle is reader-supported. When you buy through our links, we may earn an affiliate commission. Learn more

The Best Cleaners for Fiberglass Boat

Written by Anthony Roberts / Fact checked by Jonathan Larson

Fiberglass is a widely used structural material in building boats. Usually, it is applied with a layer of gelcoat that gives off its sleek image. Over time, constant exposure to harsh elements results in its wearing and damage. This gives off a muddy exterior that significantly decreases the boat’s good shape.

best cleaner for fiberglass boat

Solving this problem requires the best cleaner for fiberglass boat that will restore its former glory. However, the countless products from the market confuse boat owners. This might result in choosing the wrong one, hence wasting money or worse, further damaging the boat’s hull instead of rehabilitating it.

To avoid such mistakes, it is essential first to determine the stain type. Once you get past that, you can choose the right cleaner with the aid of this post.

With each product’s reviews, you will reach a commendable decision and put an end to your dilemma.


<strong>Top 1</strong>

Star Brite Hull Cleaner

+ Easy to use
+ Free from harsh chemicals
+ Instant cleaning results

Jump to Review

<strong>Top 2</strong>

Meguiar’s M6732

+ Recommended for those new to polishing
+ Delicate for marine life
+ Restores the vibrant color

Jump to Review

<strong>Top 3</strong>

Collinite 920

+ Restores stained fiberglass perfectly
+ Improves the wax bond
+ Longer-lasting results

Jump to Review

Best Fiberglass Boat Cleaner Reviews

1. Star Brite Instant Hull Cleaner

What’s more convenient than putting less effort and letting the product do its job? If you are looking for an easy-breezy time while combating tough stains, this STAR BRITE Instant Hull Cleaner is the perfect pick. This fiberglass boat hull cleaner sticks upon application, thus maximizing the cling time and cleaning power.

Stains such as tough waterline, rust, leaf stains, scum, dried fish blood, and stubborn old-age stains can be removed using this spray. It works perfectly on all fiberglass and painted surfaces, and ideal for vertical surfaces.

You will be stunned at how easy it is to use this product. All you have to do is spray it onto the stained surface, leave it for some minutes and then rinse it with fresh water. And, voila, you get a smooth, shiny, and perfect hull with no traces of stains. Best of all, this product possesses versatility to be used for other parts of your boat.

Just when you thought it doesn’t get any better, it does. It is entirely free from the harsh hydrochloric or phosphoric acid, which can damage and strip off the protective layers of the delicate surfaces. Instead, it uses marine-grade, and natural powerful oxalic acid formula, making it safe for the environment and your health.

On the other hand, it is advised to avoid this formula from contact with fabrics as it could lead to discoloration. Care is the top-most priority when handling this. It is practical to take extra precautions and avoid contact with other surfaces that are not intended to be cleaned.
  • Easy to use, and saves a lot of time
  • Free from harsh chemicals
  • Can be used for cleaning other boat parts
  • Instant cleaning results
  • Requires safety measures as contact may lead to discoloration
Overall, this instant hull cleaner for a fiberglass boat is a quick, and effective way of cleaning any tough stains without harming the environment.

2. Meguiar’s M6732 Marine RV One Step Compound

If you are worried about irremovable heavy oxidation, tough water spots, and scratches, the Meguiar’s M6732 is your savior. It erases moderate to heavy oxidation in just one go, thus, restoring the color and leaving a rich gloss and luster on the treated surface.

Many boat owners prefer this option since they can apply it either by machine or by hand. Either way, it produces a favorable result and brings back a brand-new looking boat that boasts an incredible high-gloss finish and vibrant color.

Although it is specifically designed to treat fiberglass and gelcoat, it can also eliminate scratches, stains, and water spots in RV surfaces, making this product an all-around cleaning agent.

Its aggressive formula reduces the steps needed in treating neglected surfaces. Despite the combative power for stains, it is delicate for your boat and marine life due to the biodegradable detergents. Additionally, its aggressive yet dainty formulation is also friendly for those new to polishing as it combines compound and polish in one.

Please note that this product does not magically remove severe defects on surfaces, as there are formulas engineered for those problems. Anyhow, this easy-to-use product eliminates moderate to heavy oxidation, watermarks, surface build-ups, scratches, stains, and stubborn spots.
  • Combines compound and polish in one step
  • Can be applied either by machine or by hand
  • Recommended for those new to polishing
  • Delicate for marine life with biodegradable detergents
  • Restores the vibrant color and shine of the surface
  • It is not ideal for severe defects on fiberglass
Overall, if you are looking for a solution that can be used either by machine or by hand while combining the compound and polish in one step, this product is undeniably the right one for you.

3. Collinite 920 Fiberglass Boat Cleaner

Choose a fiberglass cleaner that produces not only effective but long-lasting results. With that, this option is a wise investment because it restores any blemished fiberglass while maintaining its impeccable effect.

Its secret lies in its strong cleaning agents, making this mild-cut cleaner ideal for removing light mildew, discoloration, and other tough stains. It restores your boat and keeps its shine while preparing it for a follow-up wax application. This solution ensures waxes to bond to the surface successfully, making it time-efficient.

Boat owners can vouch for its user-friendly quality, especially since it removes stain easily without the effort of hard scouring. Thanks to its intense formula, it has become one of the top-rated fiberglass cleaners today. What more, it amplifies the effectiveness of the wax on its surface, producing a long-lasting clean slate.

Aside from the lesser time spent in fiberglass boat cleaning, one more good thing about this is its pleasant smell making users unbothered whenever it’s cleaning time. It is convenient, user-friendly, and exceeds expectations, minus the awful smell!

For all that, one minor weak point is its packaging since it lacks a dispenser cap, making the application a bit sloppy. You will have trouble dispensing the desired amount that you want to apply. Other than that, consumers promise favorable results upon use.
  • Restores stained fiberglass perfectly
  • Prepares the surface for the follow-up wax application
  • Improves the wax bond
  • Longer-lasting results
  • Pleasant smell
  • Dispensing and application can be quite a challenge
In summary, this mild-cut cleaner is the best option for anyone wanting to maintain their boat’s shine and stain-free slate. Unlike other cleaners, it is free from foul smell, making it friendlier for users.

4. Davis Instruments FSR Fiberglass Stain Remover

Transom, rust, oil, exhaust, and waterline stains on the fiberglass hull are a considerable challenge. Thankfully, the Davis Instruments FSR Fiberglass Stain Remover provides a solution to these problems. It only takes brushing it onto the stained surface, letting it sit for a few minutes for its powerful chemicals to do its job.

Apart from its quick-acting solution, the product is also easy to use since it does not leave any streaks upon application. This remover truly lives up to its user-friendly feature, making fiberglass boat restoring less of a task.

The best part about this marine fiberglass cleaner is the non-abrasive gel formula that prevents it from ruining other painted surfaces and gel coat. Constant precautions are never an issue here. Thanks to the gentle formula, it cleans thoroughly without any need for rubbing or scrubbing.

The next best thing about it? It not only works wonders on dull and stained fiberglass boat surfaces, but it also restores railings, stainless steel surfaces, and even trailer boats.

However, stubborn stains can be hard to strip off using this. To achieve a stain-free fiberglass, more than one application is needed for the product to work. So, if your boat is bombarded with these nasty stains, using this might take more time and effort before you can achieve favorable results.
  • Has a quick-acting solution that allows lesser cleaning time
  • Does not require rubbing or scrubbing
  • Non-abrasive formula preventing damage to other surfaces
  • Easy application
  • Works not only on fiberglass surfaces but also stainless-steel surfaces
  • More application is required to remove stubborn stains
Ultimately, this option will leave you satisfied with its quick-cleaning action that rids nasty stains in no time. Plus, its cleaning power versatility that works on any surfaces makes it worth every penny.

5. Star Brite Ultimate Fiberglass Stain Remover

Investing in a fiberglass stain remover that works in most surfaces is a wise thing for consumers looking for a bargain. On purchase of the Star Brite Ultimate Fiberglass Stain Remover – New Gel Spray Formula, you can have such a multiple-purpose product in hand. From fiberglass, rubber, painted surfaces, plastic, to upholstery, it leaves no stain undone.

Its formula is specially crafted to be tough on stains but gentle and safe on any surface. A plus advantage of this gel spray formula is its easy-to-use feature. All you need to do is spray it on the desired surface, wait a few minutes, then rinse it. There is no need to scrub since the solution penetrates the stain and dissolves it.

Removing mildew stains on vertical surfaces is a piece of cake. Thanks to its gel formula’s maximum cling time and cleaning power, waterline stains, and yellowing on your fiberglass boat hull will become a thing of the past.

Moreover, this is safe for the environment and for you, as it does not contain any dangerous and caustic acids that may cause problems on your boat instead of restoring it.

Please take note that precautions should be taken to avoid the product from having contact with bottom paint, boat trailers, decals, and other surfaces not intended to be cleaned, since it may cause adverse reactions.
  • Works not only on fiberglass, but on plastic, rubber, and upholstery
  • No scrubbing required
  • Easy to apply
  • Easily dissolves mildew stains
  • Does not contain dangerous and caustic acids
  • Contact with bottom paint, boat trailers, decals, or other surfaces not intended to be cleaned may cause adverse reactions
By and then, this product is an excellent catch as it is easy to apply and dissolves stain on many surfaces making it worth every penny.

6. 3M Marine Cleaner and Wax

When choosing the best fiberglass cleaner, its ability to remove any stain should not be the only feature eyed on. It should go beyond cleaning and also protect the fiberglass or gelcoat shine from harmful elements like UV rays. Luckily enough, this alternative perfectly meets all descriptions at an affordable price.

Its unique liquid formulation is specially crafted to rid your boat’s hull of stains like light to medium oxidation, rust, and exhaust stains. In just one application, the boat’s original color is revealed.

You will adore this marine cleaner and wax as it combines a compound that restores shine and keeps your boat polished and protected even under the sun’s rays. Not to mention, it is also easy to apply as it leaves no streaks and works effectively on fiberglass, gelcoat, to RV and car surfaces.

Boat enthusiasts consider this product as a bargain since it keeps surfaces vibrant and sleek and adds a layer of protection. Thanks to its specially engineered combination of waxes, constant worry about weather and sunlight will cease to exist, giving you more time to enjoy your boat’s beauty and shine.

Nevertheless, this product is not an ideal solution to clean aluminum surfaces.
  • Polishes the fiberglass surface as it cleans
  • Protects your boat from the harmful rays of the sun
  • Leaves no streaks upon application
  • Works on RV and car surfaces
  • Lesser time is spent as it combines cleaning and polishing
  • Not ideal for aluminum surfaces
In a nutshell, this fiberglass cleaner is recommended for those looking to spend less time polishing their boats. Its power to clean, polish, and protect fiberglass surfaces in one bottle, will never disappoint you.

7. Bio-Kleen M00607 Fiberglass Cleaner

This fiberglass cleaner by Bio-Kleen is a worthy purchase. It gets rid of stains on almost all surfaces at home, boats, and even RVs. At the price of one bottle, nasty scums, rust, algae, corrosion, and chalking will disappear. Fiberglass, tiles, porcelain, granite, and metals will come out as new as before.

Beginners will have no trouble applying this product as it penetrates the surface quickly. Its fast cleaning action goes through any spots and dissolves it in just a matter of seconds.

Many boaters choose this product as it is non-abrasive, yet leaves a wide range of surfaces clean. Fiberglass boats, swimming pools, toilets, shower walls, and bathtubs, are left sparkling clean without the need for scrubbing.

This is a great option since it works well both by hand and by machine. Even though its tough formula breaks down stains rapidly, it remains environmentally friendly. This cleaner is free from aerosols and any other toxic chemicals that may be harmful to marine life and for the boat’s gelcoat.

However powerful this solution may be, getting rid of darker stains will require more time and patience. The fumes could be a bit strong too but are easily washed away with water without staining.
  • Works on a wide range of surfaces apart from fiberglass
  • Dissolves any spots and stains in a matter of seconds leaving it sparkling clean
  • Easy application
  • Can be used both by hand and by machine
  • Free from toxic chemicals
  • Fumes may be a bit strong
  • Darker stains are harder to get rid off
Overall, this product will leave you satisfied with its fast and effective cleaning ability that is safe to use. Its power to clean more than fiberglass surfaces efficiently makes it stand out among the rest.

8. Better Boat Hull Cleaner for Fiberglass

If you need a hull cleaner for fiberglass boat that instantly does all the work, look no further than the Better Boat Hull Cleaner for Fiberglass. It is an all-around cleaner that removes built-up dirt, discoloration, fish blood, waterline, algae, grime, and grease.

Its effortless cutting through stain technology is made even better with the easy to apply quality. The three-step instructions include applying it on the desired surface, relaxing and waiting for the product to do its job for two minutes, and finally rinsing it off. You will get to enjoy more time with your boat rather than cleaning it.

New and old stains in your hull will no longer be a problem since this hull cleaner targets light to stubborn stains. It thoroughly dissolves them on contact and leaves no residues behind.

Furthermore, boat enthusiasts love the product’s versatility. It not only works wonders on fiberglass surfaces, it also cleans gelcoat, paint, and aluminum surfaces, making it as new as before with minimal effort!

If you are specifically looking for a product to whiten your yellowed hulls, this cleaner is a recommended brand.

The only downside with this product is its strong and harsh smell that pierces through your nose when you use it. You have to wear protective masks, and gloves to avoid irritation.
  • All-around cleaner, from gelcoat, painted, and aluminum surfaces
  • One application is enough to clean stains without brushing
  • Turns yellowed surfaces into its original color and keeps it shine
  • Works on contact
  • Strong and harsh smell requires you to wear protective gear
In a nutshell, this is an excellent product that works on contact and dissolves stains in at least one application.

9. MaryKate MK2032 Hull & Bottom Cleaner

If you are looking for a product that is made specifically for fiberglass, then MaryKate MK2032 Marykate On & Off Hull & Bottom is the product for you. It removes pesky stains like waterline, rust, algae, and gas exhaust. It promotes no harm to the gel coat, keeping you at ease when cleaning.

You can rely on this effective fiberglass hull cleaning. In fact, its phosphoric acid, oxalic acid, and ethoxylated nonylphenol are guaranteed to erase brown hull stains instantly.

This acid-based cleaner tears through the toughest and the most stubborn stains that most cleaners fail to get rid of. You will never be disappointed with its cleaning power as it leaves touched surfaces clean. So, if you feel stressed out about that impossibly removable stain on your boat’s hull, this is your solution.

It also makes cleaning time hassle-free since it is easy to use. All you have to do is brush it on and rinse it off. It is that simple.

On the other hand, protective gear must be worn, and extreme precautions must be carried out when using this product as it may cause irritation.
  • Removes the toughest and the most stubborn stains that most cleaners fail to
  • Works consistently
  • Easy to use. All you have to do is brush it on and rinse it off
  • Restores old brown hull stains to its original color
  • Specially made for fiberglass surfaces
  • Contact with this product may cause irritation
To conclude, this option is a great bargain. It is specially engineered for a fiberglass hull, tackles the toughest and most stubborn stains, and saves you more time.

10. Bio-Kleen M01609 Fiberglass Acid Hull Cleaner

Fiberglass cleaners that are both effective and safe for the environment are pretty hard to find these days. Most products that are guaranteed to be effective contain harmful chemicals like aerosol that damage the environment. Fortunately, with this choice, cleaning your boat never compromises nature’s safety.

You will be surprised at how quickly it dissolves stains without rubbing or scrubbing. You can apply it with a rag and even a sponge paint roller. The only effort you need to do is to wait for 30-60 seconds and rinse it off.

This is an excellent choice if you hate chemicals and toxic ingredients. Its non-abrasive nature makes it safe to use also on aluminum surfaces. Since it is acid-based, it is sure to erase stubborn stains and dirt like limescale, chalking, and algae. You don’t have to worry about scrubbing as it cleans effectively on its own.

Regardless, one thing that made me disheartened about this product is that it may cause irritation. To avoid this, you should wear protective gloves.
  • The aerosol-free formula makes it safe for the environment
  • Cleans spots and stains easily without the need of scrubbing
  • Acid-based but not toxic
  • Can be used on aluminum surfaces
  • Effectivity does not compromise marine life safety
  • Wear gloves as the solution may cause irritation
To sum up, this is an excellent choice for boat owners looking for a solution that works without the harsh and harmful acids.

11. Star brite Non-Skid Deck Cleaner & Protectant

These days, the power of a fiberglass boat cleaner does not lie on its effectiveness to clean stains only. Boat owners also consider its ability to protect cleaned surfaces and prevent it from future staining and weathering. Fortunately, the Star brite Non-Skid Deck Cleaner & Protectant offers just that.

Made for both fiberglass and painted surfaces, its chelating agents attack deep-down dirt and leave your boat grime-free and stain-free. Additionally, you do not need to brush it nor scrub it to gain desired results.

What makes this product unique is its chelating action that targets and loosens nasty deep-seated dirt on your boat’s hull. After it cleans the surface, it then creates a coating that repels future stains, which allows you to clean less in the future. Its secret? The PTEF polymers leave a layer that acts as a barrier from any dirt.

Although it is tough on stains, it contains no harsh chemicals, unlike most products. The best part about this cleaner is it never removes wax or polish, keeping your boat gleaming after cleaning.

Apart from cleaning fiberglass, the product also does the same job on plastic, metal, vinyl, and rubber surfaces, making it worth the price. You just have to spread it evenly on the surface, wait for 2-3 minutes and rinse. There is no hassle, and it definitely saves your time.

Unfortunately, like most cleaners with less harsh chemicals, more than one application is needed to get rid of tough stains.
  • One application without the need of scrubbing can clean less stubborn stains
  • PTEF polymers protect the surfaces as it cleans
  • Creates a barrier that prevents future stains
  • Made from less harsh chemicals
  • Chelating agents remove deep-seated dirt and grime
  • One or more application is required to clean the toughest stains
In totality, this choice is perfect for boat owners looking for a product that not only cleans, but protects the hull from future deposits, stains, and grimes.

12. Boat Juice Cleaner Kit

The Boat Juice Cleaner Kit is specifically manufactured to clean both the inside and the outside. It leaves users satisfied with the two-in-one use at an affordable price.

The Boat Juice Exterior is made to effectively and rapidly clean hardened mineral deposits, water spots on fiberglass, gel coat, and glass surfaces. Furthermore, its high-grade polymer wax sealant protects your boat and keeps it shiny and spotless.

It is good to know that it is also easy to use. First, you have to spray it on those nasty water spots and wipe it off. There is no rinsing required, thus saving you more time.

The second product that comes with the kit is the Boat Juice Interior that is ideal for cleaning surfaces inside your watercraft. Coffee, food stains, and smells on the carpet, vinyl, upholstery, and foam will be removed. As it penetrates the dirty surfaces, it also leaves behind a barrier that protects it from UV rays.

Its complete bargain does not stop there, since this kit also includes Interior and Exterior Microfiber Towels for wiping the solution down!

Not only does this do its job on boats, it also wipes motorcycles, kitchen appliances, cars, and RVs clean. This choice is a must-have for anyone looking for an all-around cleaner that keeps every surface stain-free and smelling fresh.

The only drawback of this product is that it may leave your skin feeling dry after using. Wearing gloves is a must to avoid flaky and uncomfortable hands when cleaning.
  • Cleans the outside and the inside of the watercraft
  • No rinsing needed
  • Leaves a barrier that protects surfaces from the UV rays
  • Has a pleasant tropical smell
  • Also cleans kitchen appliances, cars, and RVs
  • May leave your skin feeling rough and dry
By and then, for boat owners looking for a product that cleans both the outside and the inside perfectly, this is the real deal. Plus, it doesn’t have those nasty fumes that make cleaning a hassle.

13. Simple Green Marine All-Purpose Boat Cleaner

This is another brilliant choice for those looking for a solution to clean their watercraft’s exterior and interior surfaces. It is dependable to use on all types of dirt and grime, leaving any hulls looking good as new.

Surprisingly, this all-purpose cleaner lives up to its name as it cleans counters, fabrics, cars, floors, RVs, and more. This can be your go-to cleaning agent whenever you spill your orange juice on your upholstery. With its maximized cleaning value, it comes with a light, airy scent that doesn’t leave you complaining.

Apart from its ability to dissolve different kinds of grime and dirt, it is also easy to use. All you need to do is apply it unto those unwanted stains on either hulls, decks, vinyl, and fiberglass. Finally, you scrub it lightly. Its concentrated formula efficiently removes oil, grime, gas, grease, waterline, fish blood, and more.

Although this is a cleaning agent, its uses include maintaining the shine of your watercraft and keeping it clean. It is a specially formulated, concentrated cleaning solution that removes grease, oil, gas, diesel fuel, and more, from all washable surfaces in or near marine environments.

Another reason why this product is a great purchase is it is free from toxic chemicals. It is non-abrasive, non-flammable, and is only made from biodegradable elements.

Even though it is a safer choice than most boat hull cleaners, it doesn’t work efficiently on removing heavier stains. Hard scrubbing and more patience are required before you can achieve a clean hull.
  • Cleans both interior and exterior boat surfaces
  • Can also clean countertops, fabrics, upholstery, and many other areas
  • The concentrated formula gets rid of stains with light scrubbing
  • Great for maintaining boat equipment’s shine
  • Comes with a light scent
  • Washing more stubborn stains may be a challenge
In totality, this is a smart choice for those looking for an all-purpose cleaner that cleans with less effort.

14. Weiman Tub, Tile & Fiberglass Cleaner

Removing grimes, water spots, scums is a pain. Although many cleaners promise efficient washing, they leave behind nasty residues. This formula comes to our rescue, making it a smart investment for any boat owners.

It comes with a heavy-duty formula that instantly eliminates the toughest stains, rust, limescale, and soap scums without the need for scrubbing. This is the most recommended choice among boat owners as it does a thorough cleaning, and leaves no residues on the surfaces.

It is good to know that this is made with a non-abrasive formula that works like a charm. I love how it restores my boat like new without leaving traces, unlike other cleaners that scrape off stains, yet still leave marks and scratches. Plus, it doesn’t have this unpleasant chemical smell that makes cleaning even tougher.

Besides, the product works well on tiles, bathtubs, shower stalls, porcelain, ceramics, pools, and RVs.

On the other hand, this cleaner does not excel at dissolving discoloration stains on fiberglass.
  • Contains a heavy-duty formula that leaves no traces of residues
  • Recommended for tough stains
  • The non-abrasive formula leaves your boat protected from scratches
  • Works on porcelain, ceramics, tiles, bathtubs, toilets, kitchen, pools, and RVs
  • Cleans thoroughly without scrubbing
  • Not ideal for solving discoloration
Generally speaking, this fiberglass cleaner is recommended for tough stains that ordinary cleaners fail to eliminate. It cleans hard water spots, grimes, scums, rust, limescale, and more without leaving any residues behind.

How Does It Work


The fiberglass boat, which is made with gelcoat, is a porous surface. This makes it more subject to oxidation, chalking, fading, rust, scum, and many other stains that could potentially diminish the boat’s overall appearance, and eventually, lifespan.

With a suitable cleaner that is made from powerful solutions that are tough on stains but gentle on the gelcoat, your boat can be restored. The trick? The formulas in these products are engineered specifically to seep through the stains, dissolving them thoroughly, leaving every surface clean.

Some are even formulated with wax that restores shine and keeps the boat polished. This way, you can forgo waxing and save more time.

Types of Fiberglass Cleaners

There are a variety of fiberglass cleaners available today, but the most prominent are the ones in gel and liquid form.

Cleaners in gel form are ideal for beginners, and those who want to save time. This is not only easier to apply, but it also sticks to the surface as you apply it. More convenient compared to liquid forms, consumers opt to use this.

On the other hand, the ones in liquid form are made to cover more area. The only disadvantage is it requires more skills in applying, as things could get sloppy.

Benefits and Drawbacks of Using a Cleaner for Fiberglass Boat


While fiberglass cleaners mostly offer advantages, it also comes with some disadvantages. Here are the benefits and drawbacks of using a fiberglass cleaner:


  • It is easier to remove different stains on your boat.

The powerful formula is scientifically made to remove stains from the most stubborn oxidation to the oldest waterline stains. It does the job efficiently and guarantees an excellent result.

  • It will save you more time.

Unlike using homemade cleaners, which will require more effort, time, and patience, fiberglass cleaners offer an easy and breezy cleaning time for you. Its ingredients are made to save you time and sweat from scrubbing and rubbing dirty surfaces. Instead, it penetrates itself into the stains, dissolving it, thus cleaning it faster.

  • It does more than the cleaning job and keeps your boat shiny.

Apart from saving your boat from the nasty stains, it keeps it shiny, too—especially those formulated with wax that creates a clean slate. On top of this, your boat’s original color will be restored, and its luster will be improved.

  • It adds protection.

It protects the surface from the harmful rays of the sun, and some products even leave a protective coat that shields it from future stains.

  • It allows you more time to enjoy your boat.

Rust, oxidation, waterline stains, soap scums, and other dirt add to your boat’s wear and tear, which, in turn, diminishes your boat’s lifespan. With regular cleaning, you can protect your boat from these damages. Doing so gives you more time to enjoy your boat and get the most out of its value.


  • Some chemicals and toxic materials are dangerous

Harsh ingredients used to make cleaners may pose a threat to marine life and even to you. Not being mindful of these toxic chemicals may cause skin and nose irritation that may lead to health problems. To prevent this, you need to watch out for the warning signs in the product label.

  • It may leave scratches or damages on your boat’s surfaces.

Since fiberglass is made from microscopic fibers of glass, their surfaces are sensitive and are easily scratched. If you are not cautious enough, you may cause damage instead of restoring your boat.

Buyer’s Guide

Purchasing the right kind of cleaner for your fiberglass boat is not an easy task. For one, this is the first and crucial step towards restoring your watercraft.

Hence, before buying one, you may need to take a look at this buyer’s guide:

  • Find out what type of stain is in your fiberglass

Knowing the problem is the first step. It pays to inspect your fiberglass first and determine the kind of stain. Is it light to medium oxidation, rust, or exhaust stains? Is it discoloration? Or are these stains several-year-olds and are deep-seated on the surface? After you do, choosing the right product to address those problems follows.

  • Find out the ingredients

Looking for a product with non-toxic and biodegradable ingredients is a smart choice for you and the environment. As much as possible, you should avoid harsh chemicals like aerosol, detergent, and phosphate, as these may harm the waters.

Since fiberglass is a sensitive surface, non-abrasive, and mild cleaners are a wise purchase. These are sure to clean all of those unsightly spots and stains while not leaving scratches on your boat’s surface.

Apart from protecting your boat’s surface and the environment, you also need a safe product for you. Choosing such may avoid problems such as skin irritation and breathing problems caused by the unpleasant chemical smell.

But if your boat’s fiberglass is only treated by products with a strong and harsh smell, it is a must to wear protective gear.

  • Choose the one with the effective cleaning power

This is the top-most important thing that you need to consider. No matter what, you need to find a product that works consistently in cleaning the stain in your fiberglass boat. Choose a solution that is tough on the waterline, oxidation, fish blood, scum, and many other stains, all the while remaining gentle on your boat’s gelcoat.

An ideal cleaner will strip the stains off and restore its original color without stripping the paint on the surface. As much as possible, choose a product that washes dirt and stain with light to no scrubbing.

Speed is also one of the factors that equate the effectiveness of a product. With this considered, choose the one that possesses a fast-action formula. The faster it cleans, the better.

  • Purchase a product that has the versatility

Apart from the cleaning power, you should also consider the one that cleans more than just fiberglass surfaces. This is a smart investment as you get the most out of your money.

  • Choose an easy-to-use product

A gel-type cleaner is the most recommended easy-to-use product by boat owners. This ensures easy application since it clings to the surface immediately, thus, saving you more time. A product packaged with a dispenser cap is also a plus.

  • It should protect your boat from UV rays and future stains

The best way to clean fiberglass boat is also protecting it. Just like the human’s skin, the fiberglass surface becomes damaged when exposed to the UV rays. It could potentially lead to oxidation, cracks, and discoloration. To avoid diminishing your boat’s physical quality, investing in a cleaner with protectant helps.

Solutions with PTEF polymers that leave a coating while it cleans are also a great buy. This acts like a barrier that protects the fiberglass and repels stains, ensuring a long-lasting shine, free from filthy dirt and stains.

Care and Maintenance

Just like owning a car, keeping your boat’s top shape requires maintenance. As a boat owner, it is your responsibility to keep it clean, preventing it from succumbing to wear and tear that could eventually take a toll on its performance and lifespan.

To give you a heads up, here are the following tips to keeping your boat’s ship shape:

  • Clean it regularly.

Keeping your boat clean and sticking to a schedule to wash dirt and stains is on top of the list. Doing so prevents stains, especially oxidation, from sitting deep into the surfaces. This goes the same for the interior areas. You need to keep your carpet, foam, and upholstery clean from stains and dirt to avoid pesky mold and stink.

The key here is consistency. If you follow through this, you can spot early damages and act on it before it gets out of hand.

  • Use wax after cleaning it.

To keep your boat vibrant, shiny, and protected, polish it with wax after the regular cleaning. It is good to note that this keeps your boat protected from the sun’s harmful rays and repels stains. So, the next time you go on your fishing trip, you’ll have to worry less about those nasty waterline stains.

  • Never neglect to replace your pump

The pump does the job of getting rid of the water that goes into the boat. If it malfunctions, problems with your fiberglass boat could arise. To avoid this problem, it is recommended to replace it every year if you use your boat most of the time.

Frequently Asked Questions


Who makes the best cleaner for fiberglass boat?

Thanks to the power of science and research, boat cleaners and equipment are made possible. But with the range of products available, you can’t guarantee that all of them stay true to their promises of cleaning your fiberglass boat.

To save you from this inconvenience, here are a few top-rated and trusted manufacturers that boat owners stick to:

  •  Star brite
  • 3M
  • Better Boat
  • MaryKate
  • Bio-Kleen

Among those, you can choose a product to clean fiberglass boat that is ideal for you. Additionally, they are made from formulas that are tried and tested to rid of any stains without much effort and time, guaranteeing you a smart choice.

What do you use to clean a fiberglass boat?

Aside from those mentioned products that increase efficacy in your boat cleaning, a homemade fiberglass boat cleaner is also a convenient and the most environmentally-friendly go-to.

To make your fiberglass cleaner at home, all you need is to mix equal parts of baking soda and water. Shake these two ingredients together, and apply it unto the boat’s surface using a sponge. You can even simply spray it unto the stained surface. After a few minutes, wipe it with a microfiber towel.

Keep in mind that baking soda is an abrasive chemical compound and may leave scratches on your fiberglass if used without precaution.

How do you get stains out of a fiberglass boat?

As a boat owner, it is necessary to know how to remove oxidation from fiberglass boat since this is the first enemy of a porous surface. As much as possible, when choosing a product to rid of oxidation, purchase the least abrasive one to avoid leaving scratches on your boat.

Apart from oxidation, dark stains are also a challenge to clean. Thankfully, there is a cleaning hack for this. All you need to need are white towels or cloth and hydrogen peroxide. After placing the handful of white towels on the stained surface, pour hydrogen peroxide until they are soaked enough.

Leave it overnight. The next morning, remove all of the white towels and rinse the surface.

Mixing equal parts of baking soda and water is also one of the must-know boat cleaning hacks to clean your fiberglass from general stains.

How to clean boat hull fiberglass?

The first rule of thumb in cleaning the hull is to avoid using muriatic acid since this could damage your boat instead of restoring it. Instead, use a reliable fiberglass hull cleaner to remove any stains.

But before anything else, you should prepare your hull for cleaning by thoroughly washing it. Next, choose a reliable hull cleaner. It is always clever to follow instructions and not let the product sit on the hull surface for too long.

Light stains may be removed by one application. Moderate ones require more than one application and light brushing to rid of deep-seated stains.

Please note that you need to choose a cleaner that does not harm your hull’s paint or gel coat. Once you’re done with cleaning the stains, washing the residues comes next. Then, let it dry and apply wax for protection against future stains.

How do you clean a fiberglass boat deck?

Knowing how to clean fiberglass boat deck without the hassle of hard scrubbing and rubbing starts from purchasing the right boat deck cleaner. The products mentioned above are, by far, the most top-rated and sought-for by boat owners when it comes to cleaning their watercraft’s deck.

Where to buy fiberglass cleaners?

When you are looking for a trusted marketplace that sells fiberglass cleaners at an affordable price, Amazon is the best place to go. They are always on sale, and they offer a vast selection of products for every customer.

Besides their fast and inexpensive shipping wherever you are on the globe, you can always expect that they place their customers’ satisfaction on top of their priority.


With all the products available, stains will never stand a chance to ruin a great water adventure ahead. While that is good news, this wide range of selection potentially confuses customers too.

To avoid this dilemma, we are more than willing to help you make the right decision in choosing the best cleaner for fiberglass boat.

We want to share this post to you to provide answers to your queries, including information about cleaning your fiberglass boat. Hopefully, this would guide you in keeping your boat not only stain-free but in its top shape.

5/5 - (3 votes)