Harbor Safe Marine Care Products
Waxes, Cleaners & Polishes

Marine 31 Mildew Stain Remover 128 oz.

Marine 31 Mildew Stain Remover  128 oz.
Remove stubborn mildew stains – FAST!

Marine 31 Mildew Stain Remover quickly and safely removes stubborn mildew stains on virtually all marine surfaces, including vinyl seat cushions, rubber fenders, fiberglass, gel coat, canopies, and more! Marine 31 Mildew Stain Remover forgoes volatile cleaners and instead relies on smart chemistry; even the most severe mildew stains are no match for the incredible cleaning power of Marine 31 Mildew Stain Remover.

Marine 31 Mildew Stain Remover is the best boat mildew stain cleaner available!If you’re a boater, chances are you’ve dealt with the seemingly lasting results of mildew stains on vinyl cushions. If you’re reading this product description, chances are you’ve been less than satisfied with the performance of other so-called marine stain cleaners. Fortunately for you, we’ve compared Marine 31 Mildew Stain Remover against other marine stain removing cleaners and have found that it removes mildew stains faster, with less effort.

Not all marine mildew stain removers are created equal! Most over-the-counter marine mildew stain cleaners rely on heavy concentrations of bleach and other volatile chemicals that actually cause more harm than good. But Marine 31 Mildew Stain Remover removes stubborn mildew stains without discoloring, dulling, or drying out vinyl surfaces.

Best of all, it still retains the powerful cleaning ability to remove mildew stains – FAST and in the convenience of a spray bottle. To use, spray and allow to dwell for up to three minutes before thoroughly washing away. You can use a brush or microfiber towel to agitate the surface. Once done you can say goodbye to the mildew stains! You can safely use Marine 31 Mildew Stain Remover on vinyl cushions and chairs, rubber fenders, fiberglass, canopies and boat tops. But don't forget, Marine 31 Mildew Stain Remover can also be used inside the home as well! Use it to clean and remove mildew stains from tile, grout, showers and bathtubs, counters and sinks.

Use Marine 31 Mildew Stain Remover on:
  • Vinyl cushions and chairs
  • Rubber fenders
  • Fiberglass
  • Gel coat
  • Canopies
  • Boat tops
Marine 31 Mildew Stain Remover works wonders for household cleaning as well! Use this professional strength formula to clean tile, grout, showers, bathtubs, counters, and sinks.

Marine 31 Mildew Stain Remover works FAST!Directions:
  1. Spray directly onto surface and allow 1-3 minutes for penetration.
  2. If necessary, agitate surface with a brush or terrycloth towel.
  3. For stubborn stains, allow cleaner to penetrate for 5 minutes before agitating.
  4. Thoroughly rinse and dry surface.
  5. Follow with Marine 31 Mildew Stain Guard to protect treated surfaces.
128 oz.

Made in USA

Federal regulations prohibit the shipment of this products by air, UPS 3 Day, UPS 2, or US Mail. This item is shipped by UPS Ground only. Sorry but no APO or FPO addresses.

Marine 31 Mildew Stain Remover 128 oz.
Item #: M31-372
Our Price: $49.99
Availability: Usually ships the same business day

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Product Reviews

51 Reviews
92% (47)
2% (1)
2% (1)
2% (1)
2% (1)
96% Recommend this product (49 of 51 responses)
Amazing Product, never used anything better
This product is by far the best to use on boat seats I've ever seen or used. Looked horrible before, like new after use. Simple answer, just give it a try and you'll never buy anything else again. see photos!
Crestline Ohio
Wonderful stuff
This is great fo removing mold and conditioning marine furniture and boat. Fast shipping a++++
Cedar Creek Lake, TX
This stuff works!
After trying many, many other mildew removal products, I was ready to give up on an old boat that had been sitting in a boat house for 4 years. A quick spray with Marine 31, let it sit for 3 minutes and the mold/mildew seemed to vaporize. This picture was the first application without scrubbing. A second application and wiping with a cloth finished the job.
ProsFast and effective.
ConsNo complaints after three years of using it.
Edwardsville, IL
This Stuff is a MIRACLE!
This stuff is a miracle---gets rid of mildew before your eyes! Some of the big/older areas needed to sit for a couple minutes but it's amazing how great your covers & seats look afterward. I even used it in the clear shower grout and it made a huge difference just on the 1st use! I got the gel version to use on the shower next time so it will stay in place longer. I never thought anything could work this well!
ProsWorks like a miracle!
Best I've seen
Really works to get the black mold.
ProsEasy, quick.
Spring Hill, FL
Great Stuff that actually does what it says. 70 year old native Floridian APPROVED!
This product is absolutely amazing. Our boat looks new again. Thank you for a great product.
My wife told me we had to get rid of the boat because the seats were so ugly. I sprayed on Marine 31 Cleaner and without even scrubbing the mildew stain just disappeared. I thought it would take two days to clean the boat but I was done in four hours. My boat hasn't looked this good since 2000 when it was new. Thank you very much!!
Awesome mildew remover/ Product
I have been using this product for 2 years. First time I used it could not believe the results. Once you use this product you will never purchase another brands Mildew remover
ProsI highly recommend!!!!!!
Marine 31
I've been using Marine 31 for a number of years and it is perfect for getting my boat seats looking fresh after winter storage!
Economy indiana
Best product ever
If you have mildew on anything just spray this on you can watch it die and disappear. No work at all. It is like magic! Sprayed it on my mildew covered boat canvas and only had to rinse it off. Sprayed it on the boat itself, the boat seats and the house. It works. Don’t buy anything else
The best cleaner
This removed spots that were on my boat for eight years. I cleaned my entire 20 foot pontoon boat in about one hour, Just sprayed it on waited three minutes and hosed it off. You could just watch as the spots just disappeared. I had spent hours and at least ten different cleaners trying to remove the mildew spots on my light tan seats and couches.
Prosexcellent product
Long Lake ny
marine 31 mildew remover was one of the best products I have used.
sprayed it on my white seats that were almost black with mildew wacthed it just melt the mildew away only had to use a scrub brush on very few spots nice product.
Couldn’t Believe My Eyes
The heavy black mold and staining covering our boat seating literally disappeared before my eyes. We tried everything to no avail, the mold would not come out of the tiny textures of the vinyl. This product removed it in three minutes and all I had to do was rinse! I really wish I had taken before and after pics! Definitely buy the gallon and spray bottle pack. If you have a lot of mold and seating it’s worth the money and you’ll need more than one bottle.
Does everything it says it does
We bought a used boat and the seats were very moldy. We sprayed on the mildew remover and watched the mold disappear like magic. We couldn’t be happier with the purchase.
LaGrange, Georgia
Don't waste your money on this product. Go buy bleach. It is basically the same thing and will probably work better. Did not remove mildew from my Pontoon boat seats. Yes I followed all instructions.
Did not remove light to medium mildew stains from my pontoon boat seats. Did not even make a dent in heavy mildew stains. Based on odor I would say that product is nothing more than bleach that has been repackaged. Live and learn....
ConsExpensive and does not work well
Best Mildew Remover
This product is awesome!! Removed mildew from our boat after it had been sitting for 2 years. We tried multiple other products to no avail. Marine 31 mildew remover did the trick with little effort.
Rideau Canal Ontraria Canada
could not believe it
could not believe it
worked better then any other mildew remover on my pontoon
tried a few other brands but know I'll stick to Marine 31
and now show off my brand new looking seats
Conswould recommend wearing rubber gloves
Knoxville, TN
Best stuff I've ever used!
I've tried everything over the years for the stubborn mildew on my boat seats. And having to scrub and spend hours cleaning the boat at the beginning of the season. Nothing compares to Marine 31 at all! I just sprayed it on, rubbed it in and let it sit for a bit and it took all the mildew right off!
A wonderful product to use works better than anything that i have used in the past works great on above ground pools & vinyl seats
One of the best products i have ever used
Warrior River Alabama
Nothing better for mildew, mold and spider droppings.
This stuff is great for hundreds of applications. We use it on boats, golf carts and is great at removing green mold from concrete with absolutely no scrubbing. We live on a huge reservoir in the south where humidity abounds. This years during the "break out the summer toys routine" I demonstrated Marine 31 Products to my neighbors. They could not believe the fast results when cleaning Vinyl seats and boat tops. Spray it on, let it soak a few minutes, brush it and rinse it, DONE! Some neighbors have ordered others will be. GREAT STUFF.
Fabric and Vinyl Cleaner and Vinyl Protectant work well also.
works well on mildew
love it works easily
Columbiaville, Michigan
Marine 31 Mildew Remover
I've been trying for the last five years to get the mildew off my boat seats. The year that my husband passed away I decided not to open the boat and uncover it. The next year when I uncovered it all of the seats and the deck were covered in mildew. I tried everything that I could think of to get that mildew off but it would not budge. That was five years ago and this year I discovered Marine 31. It was easy and extremely effective. The mildew is no longer even noticeable on my seats or my deck! It's like having a brand new boat again! I would recommend this product to everyone.
Key Largo, Florida
Great product
This product is perfect for removing stains off your boat. My boat was just about ruined from the white fly treatment spray from my neighbor’s yard. I applied the product on the seat cushions, scrubbed, and repeated. Cushions look new. I sprayed two squirts on the non skid, which was just about black, and let it set for a few minutes. Didn’t touch it. Sprayed it off, and it was white. The product is great. Use caution though, it will burn your skin,
New Jersey
Mildew Remover
Wonderful! My boat had a seriously caae if mildew. Seat were totally black and we were going crazy.

We spray the Marine 31 waited 3 minutes and cleaned with a wet rag the seat wat white again.

I love it! I called it Miracle 31! Now everyone in the Marina is using it
ConsI burn my hand because i didn't? use gloves and the liquid was so powerful that disintegrated the bottle
Cumming, GA
works great, but packaging is faulty
Gallon container had been opened and 2 small strips of tape to keep closed. There was no sealed vinyl under the plastic cap. Not sure how much leaked out, but paper packaging was all wet.
truly amazing !
WOW, spray on, rub lightly, wait 5 mins. apply again if needed,wash off with clean water,LOOKS LIKE NEW ! I used on boat seats that were badly mildew stained I really didn't think that the stains would come out but totally stain free. Very easy to use, make shure to wear gloves, will cause skin to burn after about an hour or so .Great product that really works .
Little Rock, AR
Amazing Cleaner
I cleaned our boat seats with 31 this past weekend! I was in total awe of how it worked. One spray, one wipe and the horrible mildew was gone! A true miracle cleaner!
Palm Coast
great cleaner
i ordered the small bottle and liked it so much i ordered the one gallon size
Best mildew cleaner EVER!!!
Was able to get 3 year old mildew stains out of my boat seats. Thought it would be impossible until I purchased Marine 31. Now they look as good as new.
ProsReally works