$5.95 Flat Rate Shipping*!
Harbor Safe Marine Care Products
Waxes, Cleaners & Polishes

Marine 31 Mildew Remover 20 oz.

Marine 31 Mildew Remover 20 oz.
Remove stubborn mildew stains – FAST!

Marine 31 Mildew 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 Remover forgoes volatile cleaners and instead relies on smart chemistry; even severe mildew growth is no match for the incredible cleaning power of Marine 31 Mildew Remover.

Marine 31 Mildew Remover is the best boat mildew cleaner available!If you’re a boater, chances are you’ve dealt with stubborn 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 mildew cleaners. Fortunately for you, we’ve compared Marine 31 Mildew Remover against other marine mildew cleaners and have found that it removes mildew stains faster, with less effort.

Not all marine mildew removes are created equal! Most over-the-counter marine mildew cleaners rely on heavy concentrations of bleach and other volatile chemicals that actually cause more harm than good. Marine 31 Mildew 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!

Use Marine 31 Mildew Remover on:
  • Vinyl cushions and chairs
  • Rubber fenders
  • Fiberglass
  • Gel coat
  • Canopies
  • Boat tops
Marine 31 Mildew 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 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 Guard to protect treated surfaces.
20 oz.

Made in USA

Marine 31 Mildew Remover 20 oz.
Item #: M31-370
Our Price: $21.99
Availability: Usually ships the same business day

You May Also Be Interested In These ...

Product Reviews

143 Reviews
88% (126)
4% (6)
2% (3)
2% (3)
4% (5)
90% Recommend this product (129 of 143 responses)
Pittsburgh, PA
Magic in a bottle
We pulled our boat out of storage last week and all the vinyl was covered in mold and mildew. After 2 hours of scrubbing with mold and mildew remover and then trying a magic eraser - I was very upset thinking we would have to have the cushions recovered. The mildew had stained all the cushions and I couldn't get them to come off. I found this product online and figured I would try it before searching for someone to recover our seats. This stuff is MAGIC! I didn't even have to scrub the spots. It took awhile for the stains to disappear - but after about 15 minutes - every single spot was GONE! I will buy this product every year - and I am going to try the mildew preventer before we put the boat away at the end of the summer. HIGHLY recommend this product!!
Lillington NC
Marine 31 Mildew Remover
Absolute wonderful product. For health reason, boat sat for two years in North Carolina's humid, moist weather. Was covered with canvas boat cover for 1 year. Last year sat out in elements uncovered. In effort to clean, I researched internet and decided to test four methods of removing mildew: 1) Marine 31; 2) 3M mildew remover; 3) comet spray gel (vinyl only); and 4) magic eraser. Applied all 4 products to boat platform, left for 5 to 10 minutes. Marine 31 results were unbelievable. Person that was helping me could not believe the difference in the results as compared to the others. Family and Friends that have visited, I take them out to see the boat. Also boat owners, they understand the effort and frustration in trying to removed mildew/mold. Needless to say, they have ordered the Marine 31 to clean their pontoon. The mildew//mold on platform was heavier, darker, and thicker than what is shown in the cushion pictures below. It was just the only items I didn't get cleaned before I ran out of Marine 31 and have reordered. A picture is included to show how great the platform looks now. Like New. It was only when I was reordering to complete the project (cushions shown) that I decided I had to write the review. So wish I had a before and after on platform. Writing reviews is out of character for me, BUT I had to let others know. I have invested too much time in previously cleaning our boat and by no mean got the results obtain with Marine 31. The Marine 31 actually removed the gray spots left from previous cleanings where mildew stain could not be removed. The boat is a Renken (oldie but goodie) with lots of wonderful memories. My excitement from using the Marine 31 Mildew Remover has given me such confidence in this Brand that I will be ordering their oxidation products.
ProsQuick, efficient, and does the job. Spray on, leave 5 to 10 minutes, wipe off Cleans much older (gray) mildew stains that were left when previously clean the boat (3 years ago)
If you want something to make your life 1000 times easier when removing mildew off any surface, this is the product. It will clean battery boxes, t-tops, cushions, non-skid, and also anything not marine. This product will legitimately knock mildew out with one simple spray! Keep up the good work Marine 31!
ProsEasy to use. Tough on mildew. Very well priced.
Worked great. Only took minutes to kick in and wiped right away.
ProsTook stains off with no effort or scrubbing.
ConsOdor of bleach that lingered.
Zephyrhills FL
Mildew Remover
This is an awesome product. My golf cart seats look almost like new. And your fast service is unbelievable!!!!! I ordered it one day and the next day it was at my door. Couldn't believe it!!! Thanks for everything.
N.w. florida
Pure magic
Owning tons of boats in my life. They all get dirty from time to time,but when they get wet and mildew forms i was finding it difficult to remove the black mildew. Marine 31 is by far the best cleaner out there.
Oak Run, IL
My boat seats had mildew spots for several years and I had tried a number of products that said they would remove mildew. None of these products worked. One spray of Marine 31 and the spots were gone. I will recommend this to all my friends at the lake.
Mold stains are gone
As many have already stated, the product definitely removes the mold and stains. The product did cause color fading to a cleaning rag and a sweatshirt, so I’m not sure about the lack of harsh chemicals as advertised. Only time will show effect on seats....
Somers point nj
Works as promised
Best product I've ever used on marine vinyl. It does contain.bleach though so it will stain clothes.
Farmingdale, New York
I used this for spot cleaning on some vinyl boat cushions.
This product works well. About the same as other mildew removers.
It has a heavy bleach smell which makes me think that bleach is a primary ingredient.
Be sure to thoroughly rinse this stuff off the surface of vinyl seats and cushions then follow up with a good application of your favorite protectant.
The only reason I wouldn’t recommend this product is because of the price.
ProsWorks as advertised.
ConsPrice. You can get the same results with properly diluted household bleach. Or you can get a Mold and Mildew product by the gallon at your favorite big box store for a fraction of the price,
Brewerton, NY
Fantastic product
I tried other products over the years and this beats them all, hands down! No SCRUBBING! it works like magic. I don't dread cleaning my boat anymore.
Louisville KY
Best I’ve ever used
I had a mildew stain on my boat seats and used 2 different vinyl cleaners without success. Bought this product and within 30 seconds the stain was gone. This stuff is the real deal!
I had a mildew problem on my boat seats. I tried every off the shelf product I could find and nothing touched it. I found Marine 31 on an internet search and decided to try it. It literally melted away the mildew in seconds before my eyes. Amazing. My seats look like new.
ProsNo scrubbing. Just spray it on then rinse it off.
ConsDon't let overspray get on gelcoat or other finishes. Rinse it well with fresh water.
As Advertised!
I had stubborn spots on my boat upholstery and tried so many products. Nothing took them all the way out. Gave Marine 31 a shot, I’ll be damned, it worked! I’m very pleased.
Save your money. Useless on tough mildew
I see all these good reviews. I paid about $30 for this product and its trash. I'm so upset to have wasted that money and shipping cost. It didn't remove a single Speck of mildew off of my vinyl cushions. Shame on you. I don't know who you've got the reviews from. It was probably dirt they could have wiped off with a cloth.
It definitely does not work on any tough mildew.
ProsNo Pros. I worked long and hard trying to scrub the mildew off of these cushions to no avail. Used a good portion of the cleaner without a single stack of mildew being removed.
ConsAll cons. Will NOT remove tough mildew. No matter how hard you scrub or try or repeatedly follow these directions to a T, you'll be out of money.
Cape Coral Florida
Wow just amazing
I had tried several other products but nothing cleaned my vinyl seats like Marine31.
Madison Lake, MN
This product is the best I have ever found for cleaning the vinyl on our pontoon, and I have looked and purchased many many items. I wish this was sold in stores in our area and a little cheaper.
But it works fantastic and as long as we have a pontoon I will continue to purchase this product.
ProsWorks before your very eyes!
Works as advertised!
We purchased this product to see if it would get rid of stubborn mildew stains that we have tried everything to get off our boat seats. We were so happy Marine 31 Mildew Remover took it all off within minutes. The seats look like brand-new again!!! Be sure to use gloves and that the area is well-vented.
Excellent product recommend
I recommend this product 100%
Central KY
Almost Instant
So quick to remove mildew. Excellent product.
Grand Island NY
Took possession of a boat that sat uncovered for 3 years. Tried 3 other cleaners that all alleged to be the best at removing mold/mildew. Nope. Finally decided to give one last try & ordered Marine 31. WOW!!!!! Very little elbow grease needed as Marine 31 did most of the work. Awesome product. Will never buy anything else!
Best I have found!
I've had a big problem over the years with mildew on my pontoon seats. I've tried many products, but the Marine 31 line is by far the best I've tried. I highly recommend it.
ProsEasy to use. Very little scrubbing required.
Tried others, hands down this is the best!
Braselton ga
Works as advertised
Seems kind of simple but it works as advertised I sprayed it on waited 2 minutes then rinsed it off mold gone worked on the flooring of my pontoon under the rails sprayed and rinsed. Very satisfied with performance will be buying again. Read a lot of reviews and YouTube videos and landed herer
ProsQuick and simple
Georgian Bay
Easy to use, extremely useful
North Dakota
This works great. Mold on my pontoon vinyl disappeared with in two or three minutes
The best ever!!
This product is the best for taking off mold and mildew on our pontoon seats!!!
North Webster, IN
Beats all others
I have tried every marine product there is to remove mold and mildew and Marine 31 is the only one that worked. Just follow directions and it will take that mold and mildew right off.
ProsFast and actually works.
St. Charles, IL
This product worked AWESOME! had purchased a boat that had a ton of mildew everywhere.. this stuff removed it with VERY LITTLE EFFORT! This is a must have if you’re a boat owner!
Egg Harbor Township, NJ
Over the past year, I've placed orders for two different products to remove mildew stains on my boat, seats and instrument panel. None worked. I tried solutions with bleach and vinegar. Did not work.
Two weeks ago, I stopped at a Canvas Shop to inquire a remedy. They heard although never used a product called "MARINE 31" with good results. So I ordered this product. Yesterday, I went to the Marina to try and get all the mildew stains off. I am thrilled to say..."ALL the stains are GONE" !!! This product is the best. I first tested it on my driver's seat. I sprayed it, left it alone for about 5 minutes. Went back to see how it was working and the stains were GONE. Needless to say, it motivated me to get the entire boat done. After about three hours, I was done and my boat looks new! This product is truly amazing and it does work perfectly.
I HIGHLY recommend it!
ProsJust spray it on, leave alone for 3 to 5 minutes and wash off. After you spray it on, don't be discouraged with "streaks" running down the seat backs...it's the mildew coming OFF. After concertration on the tops of seats where the mildew stains were concentrated, I sprayed the entire seat, waited a couple minutes and wiped it all off. PERFECT. After being all done, I washed all the seats with a mild soap and then treated all the seats with a finish to protect it from the sun's UV.