How to Clean a Fiberglass Tub That Has Yellowed: 9 Tips!

How to clean a fiberglass tub that has yellowed could be a household problem if you don’t get rid of it immediately. Don’t worry! We have the solutions!

Fiberglass tubs are very popular as they’re both affordable and durable. They can be used as a bathtub as well as a shower, and because they’re less likely to crack than ceramic or porcelain tubs, many people prefer them.

However, there is one minor issue that fiberglass tub owners encounter – the yellowing of the tub.

As you know, fiberglass tubs are a great way to add an eye-catching design element to your bathroom. They come in a wide array of vibrant colors, and they look great in a contemporary bathroom.

But over time, the coating on the fiberglass will start to crack and leak, and it will discolor from either heat or from use.

Bathtubs get dirty every single day and it can be hard to keep them clean and hygienic. The problem is, the dirt and grime tend to make the tub look even dirtier, messier, and become a yellow stain.

What should we do?

After you read this article you’ll learn how to properly clean your fiberglass tub so that it looks new again.

How to clean a fiberglass tub that has yellowed

1. White vinegar

Did you know that you can clean a yellowed fiberglass tub with white vinegar?

White vinegar is great for removing mold, mildew, and yellow stains in the shower, which makes it perfect for cleaning fiberglass tubs.

If you have a fiberglass tub in your bathroom, it may appear dirty and dingy.

However, a simple mixture of two parts white vinegar and two part water is all that’s needed to remove the discoloration.

Mix them in equal volume and pour the mixture into the bathtub. Brush the mixture over the surface gently, then rinse thoroughly. This solution will remove any soap scum or stains from your tub.

2. Lemon water

To clean fiberglass tubs, many people use bathroom cleaner.

However, you can also use lemon to clean your fiberglass tubs and make them shine like new. Using lemon has a couple of advantages: you can clean it without having to use toxins and the pH balance of the lemons will help keep your tubs from getting yellow again.

Lemons are also very cheap, so they are economic too.

Cut the lemon into halves and you can squeeze the juice of a lemon on the dirty fiberglass fiber. Then you can brush it in order to remove the stains on the towel. Once you have cleaned all the stains, you can rinse out the excess lemon juice in warm water.

3. Baking soda


Baking soda is a great cleaning product. It can be used to clean all kinds of surfaces, including fiberglass. Baking soda has mild abrasive power that can be used to remove tough stains and dirt from your tub.

Just mix baking soda with water until you get a paste, then pour the paste into the tub to scrub it. Once you’ve scrubbed it, rinse the tub with water to make sure it’s completely cleaned.

4. Salt

Cleaning a tub with salt can be a cheap alternative to using more expensive chemicals that only address the yellowed exterior of a tub.

Diluting salt with water can be used to clean fiberglass tubs that have turned yellow because of their age.

Mix the salt with water and pour the mixture into the tub. Using a brush, scrub the tub until all of the yellow parts are no longer visible. Once you’ve completed this, rinse the tub thoroughly with warm water to remove any traces of salt, and your old fiberglass tub will look new.

5. Hydrogen Peroxide

As you probably already know, hydrogen peroxide is a substance commonly found in wipes and used to whiten teeth.

You can also use it in your bathroom to disinfect and clean certain items. If your shower room has a fiberglass tub that has yellowed, a DIY cleaning solution of hydrogen peroxide and water will work wonders for you.

Start by pouring the peroxide into your tub. Next, scrub the walls of the tub until they are clean. Finally, wash the tub by pouring water over it. As you can see, hydrogen peroxide is a great cleaner that can be used in your bathtub!

It is highly recommended that you wear protective gear when using this liquid, such as goggles and gloves because it could cause temporary blindness and irritation to the skin and eyes.

6. Shampoo

Yep, you can use shampoo to clean a fiberglass tub that’s gotten yellowed.

It works well for cleaning fiberglass tubs and sinks that have yellowed over time. All you need to do is pour the shampoo into the tub and scrub until it becomes shiny and spot-free. Then, rinse it with water until they’re no traces of shampoo left.

7. Softdrink

People don’t usually know that you can use soft drinks to clean a fiberglass tub. Using soda will help you clean the yellow stain of the tub and then, it will leave your tub sparkling clean.

Definitely, it’s a great way to remove stains from your fiberglass tub.

Softdrink such as Coca-Cola and Pepsi could give your tub a makeover. Pour your favorite beverage into the tub and wait for about 10 minutes.

Then, use a brush and rub the stains gently. The sugared substance on the drink will help rub the stains away and repair your tub. After that, rinse it quickly and you can enjoy your clean fiberglass tub.

8. Castile liquid soap

Castile liquid soap is very gentle on your skin and can be used as a body wash, shampoo, and even a facial cleanser. The mildness of this type of soap makes it perfect for cleaning the bathtub after years of neglect.

Mix 2 tablespoons of Castile liquid soap with 1 cup of water in a spray bottle.

Spray the tub down with this mixture and let it sit for 15 minutes before you start scrubbing it with your sponge or scrub brush.

Scrub all areas until they are clean and shiny again. Rinse off any excess dirt with warm water and dry the tub off completely before using it again.

9. Chemical cleaner

The chemical cleaner can be an alternative solution to remove stains from fiberglass. It helps remove yellow or brown discoloration.

These products are safe and easy to use. By following the instructions carefully, you will be able to clean your bathtub properly.

The first thing you should do is pour the product into your tub and let it sit for 5 minutes. This lets the solution sit and penetrate the stains properly. After 5 minutes, you should use a brush to scrub the stains on your tub.

How to prevent your fiberglass tub from yellowed

1. Use it according to its function

To prevent your fiberglass tub from yellowing, use it according to the function. For example, if you want to use it as a pond or aquarium, where water and pests may be present, you should never use the tub for this purpose.

You may not think you’ll cause any damage, but eventually, this may cause the tub to yellow over time. There may also be damage to it which is hard to spot at first glance.

2. Ensure good air circulation

Fiberglass normally has a yellowish tinge to it, so you have to make sure that the tub stays as dry as possible.

Yellowing is caused by accumulated mineral deposits in moist areas, such as bathtubs and sinks. But you can eliminate this with good air circulation. If you make sure the area around the tub is well ventilated, there will be enough moisture-free air to keep it dry and prevent yellowing or corrosion.

3. Clean it regularly

Spills happen. Food, bath crayons, and shampoo are just a few of the things that will stain your fiberglass tub. If you want to prevent your tub from yellowing, make sure to clean it regularly.

This will prevent stains from dulling or yellowing your tub.

How to remove tough stains from fiberglass tub

To remove tough stains from a fiberglass tub, you can try the following steps:

  1. Create a cleaning solution by mixing equal parts water and white vinegar in a spray bottle.
  2. Spray the solution onto the stain and let it sit for several minutes to allow it to penetrate the stain.
  3. Scrub the stain with a soft-bristled brush or a sponge. Be sure to scrub gently to avoid damaging the fiberglass.
  4. Rinse the area with water to remove the cleaning solution and any loose dirt or grime.
  5. Repeat the process if necessary until the stain is removed.
  6. Dry the area thoroughly with a clean, soft towel to prevent water spots.

If the stain is still present after trying these steps, you may need to use a stronger cleaning solution. You can try using a commercial fiberglass cleaner, or a mixture of water and baking soda or water and lemon juice.

As a last resort, you can try using a mild abrasive cleaner, but be sure to test it in an inconspicuous area first to ensure it won’t damage the fiberglass.


Fiberglass tubs provide a low-cost, low-maintenance option for your bathroom renovations. However, if neglected and not cleaned properly, these tubs may become dull and yellowed.

Here is the list of what you need to know of how to clean a fiberglass tub that has yellowed:

  1. White vinegar
  2. Lemon water
  3. Baking soda
  4. Salt
  5. Hydrogen Peroxide
  6. Shampoo
  7. Softdrink
  8. Castile liquid soap
  9. Chemical cleaner

If you want to clean your bathroom read how to clean plastic bathtub or a bathroom sink drain article!


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