How To Clean A Fiberglass Tub With Oven Cleaner

Ryan Womeldorf
by Ryan Womeldorf

Brand-new fiberglass tubs are built with a protective material that is smooth and glossy in nature. This is known as the “gel coat” and is meant to offer resistance to scratches and other surface damage. But over time, it can wear down, leaving the surface rough and allowing soap scum and dirt to build up.

So, how do you clean a fiberglass tub?

Spray the fiberglass tub with fume-free oven cleaner and let it sit for 1 hour. Dampen a sponge or a cloth and scrub the fiberglass tub thoroughly. Rinse the oven cleaner out of the fiberglass tub with a pitcher of water or a showerhead.

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Why Oven Cleaner?

The simple fact of the matter is that the oven is one of the most difficult places in a kitchen to clean. It can become coated in food splatterings, making it far more difficult to get a more thorough, comprehensive clean.

Oven cleaner is industrial strength, meaning that it is meant to be used on the toughest stains possible. So, when it comes time to clean your fiberglass tub, it only makes sense to implement a very tough stain remover to get the job done.

Step 1: Proper Ventilation

The first thing that you need to do is ensure that there is proper ventilation in the bathroom. This is because oven cleaner is a very strong chemical cleaner. Using it in an enclosed space is very dangerous to breathe in.

Open the bathroom door and any windows in the bathroom as well. You also should have a fan set up to blow the fumes out the window. Dangerous fumes are nothing to mess around with and having proper ventilation will not only prevent it from lingering but keep you safe while you are cleaning the fiberglass bathtub.

Step 2: Spray and Sit

This is an important part of the cleaning process. Spray the oven cleaner (fume-free if you can find it) in an even layer on the fiberglass bathtub. Start at the bottom of the tub and work your way up and over the sides.

When spraying, avoid any of the metal trim. Oven cleaner is very strong and could potentially damage the finish of the metal. Make sure that you allow the oven cleaner to work its magic on the surface of your fiberglass tub; give it around an hour or so before doing anything else.

Leave the windows open and allow the fan to push out the fumes as they rise. With the windows and door closed, you could be walking into a nasty surprise.

Step 3: Wipe

After the hour has passed, now comes the time to wipe off the oven cleaner. Use a sponge or a damp cloth to thoroughly wipe down the residue from the oven cleaner. It may take a few passes to ensure that all of the cleaner has been removed.

Take your time and thoroughly wipe the entire surface of the fiberglass tub. Not only can the oven cleaner have dangerous fumes, but it can also drip down onto the finishes of your tub and damage them over time if not properly removed.

Step 4: Rinse and Wipe

After wiping down the vast majority of the oven cleaner, now comes time to rinse. A rinse will remove any of the oven cleaner that you may have missed during the previous wiping step. You can even use your showerhead to do the rinsing.

When you’re confident that the oven cleaner has been rinsed away completely, wipe down the entire surface of the fiberglass tub with a dry towel. If the stains in your fiberglass tub are particularly difficult, you may need to perform the entire process again until the stains have been completely removed, but oven cleaner should do the trick on even the toughest of stains.

Clean on a Regular Basis

The best way to prevent a buildup of those difficult stains is to clean your fiberglass tub on a regular basis. You don’t have to do daily cleanings, but once per week should be more than enough to prevent nasty stains from becoming a thing in your life.

Make sure that you use or create a non-abrasive solution for cleaning. You can try using some warm water and just a squirt of any kind of liquid detergent. If you think that you’re going to have a little bit of a tough time cutting through stubborn grime and dirt, add some more soap to the mixture.

You want non-abrasive cleaners like laundry or dish detergents, bathroom cleaners, all-purpose cleaners, or even baking soda. Remember we want to clean the surface of the fiberglass tub, not ruin its finish.

Make sure that you use a non-abrasive applicator, too. Using steel wool, scouring pads, or scrapers can be too harsh on the surface of the fiberglass, leaving it with marks and scratches that can appear unsightly.

Can You Use Baking Soda to Clean Fiberglass Tubs?

While having an industrial cleaner available would be great, it generally isn’t something that most of us have laying around our homes. So, when the time comes to clean your fiberglass tub, you may be left looking for household options instead.

The good thing is that baking soda is a great household cleaner. All you need to do is mix it with some water to get rid of particularly tough soap scum and other stains. You’ll want to mix the baking soda with some water until it has the consistency of paste and then spread that paste over the areas prevalent with soap scum.

Leave the mixture to sit for a couple of hours, allowing the baking soda to break down the soap scum. After a couple of hours, come back and rinse off your mixture and wipe using a dry cloth or a towel. Depending on the severity of the soap scum stains, you may need to do this once or twice more, but it should work.

Can You Use Vinegar to Clean Fiberglass Tubs?

Another great household cleaner is white vinegar. It can be used to get out particularly strong odors and tough stains on myriad surfaces. It is one of a couple of household acids that can be used effectively against stains without damaging the surface that it is cleaning.

It is important that you dilute the white vinegar, however. It is quite potent and even if the acid doesn’t damage the surface of the fiberglass, the bathroom will smell like vinegar. That smell is not something that can be ignored and will require some effort to get rid of.

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How do you Get Brown Stains out of a Fiberglass Tub?

You may notice after some time that there are unsightly brown stains building up on the surface of your fiberglass tub. The best way to remove them is by using the aforementioned baking soda or some hydrogen peroxide.

Create a paste using the hydrogen peroxide and baking soda (and some water), spreading the paste over the stain and giving it around 30-60 minutes to properly work its magic on those stains. Then, all you have to do is wipe it away and rinse. The toughest stains may take a time or two in order to completely get rid of them, so don’t get discouraged if the stains aren’t completely gone.

Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

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