How to Remove Mildew Stains From Vinyl Boat Seats

If you own a vinyl boat, I bet you know very well how much damage dirt, grime, mold, and especially mildew can cause. Over time, they “eat away” at the surface, turning your boat into a piece of junk. That’s why in this guide, our focus will be on removing mildew from boat seats. Statistically, the seats are in more danger of being ruined by mold/mildew than the rest of the sea craft.

It won’t take you much time, effort, or money to get this done. However, it’s very important to know what tools/equipment to use to achieve the best possible results. So, without further ado, let us go ahead and get rid of all that nasty mildew that has taken over your seats!

What you’ll need for the Job

Boats are in constant contact with moisture. And, no matter how careful you are, mildew will form over time. The experts recommend wiping out the seats with a piece of dry cloth and avoiding unnecessary exposure to water. But what if you’re already past that stage and the seats are messed up? Here’s a list of the most useful and effective tools slash supplies that will help you deal with mold and mildew (relatively) easily:

Mildew stain remover - Marine 31

  • Mildew stain remover (it should be bleach-free)
  • A brush (preferably with soft bristles)
  • Microfiber cloth for cleaning
  • A couple of sponges (like Magic Erasers)
  • A can of protective spray

The best thing about this stuff – it’s pretty cheap and available both at local stores and online shops. For example, a decent-quality stain remover will only cost +/- 20 US dollars. In my experience, the Marine 31 mildew remover is one of the most effective vinyl protectants on the market. You can get it for 20-40 bucks depending on the size of the boat. The rest of the supplies are even less expensive.

Step #1: Spraying the Formula

A quick note before we get to it: naturally, bleach is incredibly effective against dirt, grease, grime, and mildew. But, I strongly recommend against using it on vinyl. The reason: it strips the vinyl of the oils that make it sturdy, long-lasting, and rust-resistant. Plus, bleach will have a negative effect on the stitching, essentially ruining an otherwise perfect set of seats. Again, check that there’s no bleach in your remove (Marine 31 is bleach-free, by the way).

So, just go ahead and spray the remover onto the seats. And pay extra attention to all the seams and gaps, because that’s usually where the mold accumulates (water tends to build up there). Most remover solutions need only five-ten minutes to “sink in”. If you’re dealing with stubborn stains, give it an hour or so.

Step #2: Scrubbing Off

Moving on with our How to clean vinyl boat seats of mildew guide, get to scrubbing. That’s right: no remover is strong enough to deal with the stains for good – you’ll need to do some old-school rubbing to get the seats squeaky-clean. As mentioned earlier, use a soft brush. Otherwise, you might end up scratching the seats, especially if you press it too hard. The remover did all the “heavy lifting” anyway; so, all that’s left to do is to polish everything.

Scrubbing Off

Just like we did with the spray, make sure you’re getting all the mildew and debris from all the tiny gaps in between the seats and all the other nooks and crannies. With that out of the way, arm yourself with a piece of microfiber cloth to remove any remains of the mold. I mention microfiber because it is very smooth and gentle, which is exactly what we need for this.

Wipe in a slow, circular motion, and change the cloth once it gets dirty. This is the best way to clean vinyl seats. It might take you an hour or two, but the result will be worth your while. The seats will look almost as good as new! If you feel like there’s still mildew left on the seats, repeat the whole process, starting with the cleaner-remover, the scrubbing, and the wiping.

Step #3: Using Magic Erasers

Pretty much any sponges will do, but the famous Magic Erasers (or similar ones soaked in cleaning formula) will do a far better job. There’s nothing to it: you won’t even have to scrub that hard. Get the sponges wet and go over the problematic areas that all the previous supplies couldn’t handle. Good news: since the sponges are pretty small, they make it easier to reach “problem areas”.

Step #4: Applying the Protectant Spray

Finishing up, I recommend adding a thin layer of protectant spray. As the name suggests, it will ensure the seats are well-protected against new stains and UV rays. This is a preventative formula that aims at helping the vinyl last longer. If you’re on a tight budget, just skip this part. A bottle will only cost you $10-15, though.


Alright, that pretty much sums it up! Now you know how to clean vinyl seats properly so that they serve you for a long time. You don’t really need to do much: just get the right stuff for the job (microfiber cloth, a pack of sponges, a brush, and a remover) and you’ll be done with this in no time. And if you want to learn more about boat maintenance, make sure to check my other reviews and guides on this website!

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