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How To Remove Stain From Fiberglass Door? Spot Removal

Dealing with stains is never easy, more so for sensitive materials like fiberglass. Trying to remove a small spot on the surface might lead to a damaged coating. Sometimes, the whole stain becomes worn and you’d want to redo it.

But the material used for fiberglass doors is so sensitive! What’s the proper way and how to remove stain from fiberglass doors?

Vinegar or acetone are good choices. However, you need to be careful about the amount. If you’re thinking of removing the stain of the whole door, you’d like to use a water-based stripper. 

There are a few cautionary aspects to take note of before you proceed.  If you’re willing, we have a detailed step-by-step guide for you here-

Removing Stains From Fiberglass Door: Quick And Simple

Fiberglass is a material used for many purposes. For example, many people use fiberglass instead of sheet material for duct boards. Nonetheless, in all cases, fiberglass has been a sensitive material to deal with. So you have to be selective about which products to use with it.

Before we get started with the process, let’s get you familiarized with the products you’ll need. We are trying to accomplish two things here, and different products are needed in both cases.

If you’re trying to remove a stain or spot on the exterior surface of the door, it’s easy. Removing stains on top of the coating will need a mild acid and rag. Using vinegar or acetone is preferable.

Then again, many remove the whole stain on the door to replace it with a new one. You might want that too, but it’s a bit tricky.

Tools You’ll Need

You’ll need some tools like painter’s tape, paintbrush, straight-edged scraper, and brush. It’s better if the brush is soft-bristled, or medium. Moreover, you’ll need a rag and metal containers. 

The metal containers will be used to mix and hold the mineral spirit and stripper. For the stripper, you need a non-methylene chloride stripper. On that note, here are some of the bests we recommend you use:

You should try to go for low odor mineral spirits. Also, you’ll need gloves and goggles that are resistant to chemicals for safety purposes.

Removing Spots

To remove the spot on the surface, you need to dab the stain away! Yes, it’s as easy as it sounds. 

Trey and use vinegar first, a few drops to drench a rag, and dab on the spot. Keep dabbing gently and the spot should start fading. If you see it’s not working after a long while, you can switch to acetone.

The reason we don’t recommend acetone the first is that it might damage the coating. Use only a little bit, a few drops, on a rag at first. Gently dab on the surface, don’t let it touch the surroundings. You can increase the amount of acetone slowly, and the spot will start to fade. Eventually, the stain should vanish in no time!

Removing The Exterior Coat

This requires a few safety precautions to take. To remove the stain on the fiberglass door, you’ve to ensure the safety of other parts. As well as yourself, use gloves to protect your skin.

Step 1: Ensure Safety

Any wood, PVC, or glass attached to the door should be covered. To do this, we’ll use tape. But any tape won’t do. For example, getting rid of masking tape from wood can be an ordeal. So, to be safe, we’ll use painter’s tape. 

Use painter’s tape to cover anything besides the fiberglass surface. Once you’re done with that you have to ensure your own safety! Strippers and mineral spirits are harmful chemicals. You don’t want them on your skin, and definitely not in your eyes. So equip yourself with gloves and goggles that resist these chemicals. If possible, opt for a mask too! The fume might be unbearable for a few.

Step 2: Strip the Stain

Ventilate the place you’ll be working in before you start. Now, pour a good amount of paint stripper into a metal container. Dip a flat brush into it and gently coat the surface of the door. Make sure you lather the liquid evenly at all places. If you have any latches to prevent your double-door from blowing shut, get rid of them first. It might be hard to work around them properly. 

Following the manufacturer’s instructions, let the lather dwell. The usual is around 15-20 minutes. Once the time mentioned in the instruction has passed, scrape the coating off. Be gentle with the scraper now! You won’t like it if the material is damaged to any extent.

Step 3: Get The Crevices

Use a soft bristle brush and rag to get rid of the dust and clean the crevices. Once the whole surface is stripped of the stain, clean it gently with mineral spirit. You can use a rag or a flat brush for this. Once, that’s done, well done! The stain is off your precious door!

It’s too soon to rest! It’s not optimal to keep the fiberglass without any coating at all. So you should refinish your door as soon as you can! With this thought, you’d better keep those tapes in place for now. As you’ll probably have to do it all over again for refinishing otherwise.

The process might seem hard at first but it’s as simple as removing sharpie marks from tables.


Question: Is it alright to strip the whole door of the stain at once?

Answer: it is advised you start with a small portion first, since the results may vary. Different strains have different endurance, so testing is better than regretting later.

Question: What kind of scraper is good for scraping the coating off the surface?

Answer: A scraper not too sharp is optimal for the job. You can opt for a plastic scraping tool. Make sure to scrape in one direction only. And the direction should be the same as the direction of the wood grain.

Question: Can I refinish my door immediately after taking off the stain?

Answer: To put it simply, no. You will have to give the surface enough time to dry. The door should be dry and free of residue when you refinish the door.


Way to go! I think we’ve got you through how to remove stain from a fiberglass door? We sure hope so! Give this technique a try at home, we’re sure it won’t disappoint you!

Make sure to take breaks in between work, happy decorating!