Harbor Safe Marine Care Products
Waxes, Cleaners & Polishes

55 Reviews
87% (48)
4% (2)
2% (1)
4% (2)
4% (2)
93% Recommend this product (51 of 55 responses)
By Sherry
Crestline Ohio
Wonderful stuff
February 1, 2021
This is great fo removing mold and conditioning marine furniture and boat. Fast shipping a++++
By Marc
Cedar Creek Lake, TX
This stuff works!
October 27, 2020
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.
By lakeshorecindy
Edwardsville, IL
This Stuff is a MIRACLE!
October 22, 2020
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!
By Charles
South Carolina
Great Product
September 23, 2020
Marine 31 mildew remover is the best product I have found for cleaning my boat seats and keeping them clean throughout the season.
By Dave
Lexington, ky
Mildew remover
September 9, 2020
Best product I've ever used! Wonderful when a product is better than advertised to be.
By Rocky
Best I've seen
May 29, 2020
Really works to get the black mold.
ProsEasy, quick.
By Captain D.
Spring Hill, FL
May 22, 2020
Great Stuff that actually does what it says. 70 year old native Floridian APPROVED!
By T C.
Lawrenceburg, Indiana
Not worth the money
May 20, 2020
I applied it to the seats of my pontoon boat and I can't say it worked. I can say that it reduced the appearance of mildew but did NOT REMOVE it.
By Jan
May 18, 2020
This product is absolutely amazing. Our boat looks new again. Thank you for a great product.
By Domenic C.
April 9, 2020
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!!
By Carlos P.
Awesome mildew remover/ Product
March 31, 2020
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!!!!!!
By Ronnie
Marine 31
March 28, 2020
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!
By Tom M.
Monroe, Georgia
Great Product-Terrible Packaging
March 19, 2020
I sent an email about this never got a response. This is really a great product. First time I ordered in this size. When it arrived, it had leaked all over the inside of the box and it was a mess. I would like to know what will be done about this. Not only did I lose product, but had to clean things up.
ProsLike I said above, I like this product allot, but amd extrmem;y frustrated and disappointed in not only how I received it, but that nobody from Marine 31 responded to my email.
ConsPackaging and communication.
By Claire
Economy indiana
Best product ever
August 9, 2019
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
By jim
The best cleaner
August 4, 2019
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
By Jim
Long Lake ny
marine 31 mildew remover was one of the best products I have used.
July 18, 2019
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.
By Alana
Couldn’t Believe My Eyes
July 11, 2019
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.
By Ali
Does everything it says it does
July 10, 2019
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.
By GW P.
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.
June 26, 2019
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
By Deb
Best Mildew Remover
June 20, 2019
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.
By chris w.
Rideau Canal Ontraria Canada
could not believe it
June 10, 2019
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
By Jon S.
Knoxville, TN
Best stuff I've ever used!
June 8, 2019
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!
By Jerry B.
A wonderful product to use works better than anything that i have used in the past works great on above ground pools & vinyl seats
June 8, 2019
One of the best products i have ever used
By Good M.
Warrior River Alabama
Nothing better for mildew, mold and spider droppings.
June 6, 2019
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.
By Bruce M.
works well on mildew
June 6, 2019
love it works easily
By Kim
Columbiaville, Michigan
Marine 31 Mildew Remover
June 3, 2019
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.
By Scott
Key Largo, Florida
Great product
May 27, 2019
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,
By Maritza
New Jersey
Mildew Remover
May 26, 2019
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
By Mark
Cumming, GA
works great, but packaging is faulty
May 19, 2019
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.
By andrew o.
truly amazing !
May 13, 2019
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 .
By Barbara
Little Rock, AR
Amazing Cleaner
May 1, 2019
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!
By Tracy
Palm Coast
great cleaner
April 29, 2019
i ordered the small bottle and liked it so much i ordered the one gallon size
By Mitch
Best mildew cleaner EVER!!!
April 18, 2019
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
By Walt
SW Florida
Great product.
April 4, 2019
Best mildew remover I've ever used, and I've use several different products. Easily removes mildew stain from marine upholstery. Rather pricey when purchased in smaller spray bottles but more reasonably priced in gallon containers, especially with a promotional discount applied.
ProsProbably the best mildew stain remover on the market.
ConsOther than price...none.
By Orlando
Amazing Product
March 31, 2019
It truly works as advertised. Surprisingly very little scrubbing. Word of caution, if used inside a cabin or other confine area, make sure it is well ventilated.
ProsRemoves the most stubborn mildew stains will little or no scrubbing required.
By Jamie
Kihei. Maui
Leaking bottle in shipment
February 8, 2019
Shipment arrived intact, one Bottle the lid was not tightened and the product had leaked into the box ... destroying the paper packing ... I have pictures ... it was over $80 in freight... and approx 1/4 container drained ... great product but poor shipping practices
By craig r.
Gulf shores Alabama
Mildew remover Magic !
February 8, 2019
I have a wave runner cover I was close to throwing away because of all the mildew on it. I had tried several other products with no results, but then I came across several reviews of Marine31 and wanted to give it a try. This stuff is like a magician in a bottle. You can see the mildew disappear, and my cover looks New again!
By Captain B.
Crescent Beach, Florida
It works, pure and simple.
January 21, 2019
Thank you for developing a product that actually does exactly what it is supposed to do as advertised. Ordering was easy. We've added your website as a favorite to our system so we can easily re-order when we need to.
By Bobalouee
Upper Michigan
Works good but needs to sit on material before scrubbing vigorously
December 21, 2018
Is not spray on wipe off on stubborn stains. Needs to sit on material for 5 mins then scrub vigorously. Clean off with spray nine then clear warm water. May need two applications. Dry thoroughly then apply a quality Vinyl protectant... I assume I had some very stubborn mold stains.. I tried a few different brands but this was the best for my problem. Nothing works without some scrubbing.
ProsDoes work good ..
ConsNeeds ELBOW GREASE ...
By John
Ocean City
Works Great!
December 19, 2018
I had mold on my T-Top and bolsters. I sprayed on Marine 31, waited 10 minutes and all the mold was gone. Great Product!
By Neil H.
Punta Gorda FL
Mildew remover
December 13, 2018
This is the best I have ever used for getting rid of mold and algae on my boat.
By Laurie
Raystown Lake, PA
Very pleased
October 24, 2018
I have to admit that I was skeptical when I ordered this but it really did a great job on the mildew that had developed on our pontoon at the end of this rainy summer in Central Pennsylvania. I honestly wish we would have taken before and after pics. We will definitely be buying Marine 31 again.
ProsProduct was thorough and effective quickly
By Dave H.
Milwaukee, WI
Marine 31 Mildew Remover
October 11, 2018
Works as advertised. What took me 4 1/2 hours last year with 3 people cleaning this year took 2 hours with 1 person cleaning. I have already recomended it to everyone I know that has a boat.
By Eugene M.
Ottawa, On, Canada
Great product, great results!
October 5, 2018
Rarely have I used a product that works so well. I have tried every other products combination and elbow grease with no results. Marine 31 worked on my vinyl seats on my pontoon that looked awful with black mildew stains, they disappeared within seconds of applying the product and then looked brand new! Very satisfied with the results.
By Matt
Lake Lure, NC
Works like Magic
September 27, 2018
Best Mildew remover on the market. Spray, wait and the mildew vanishes. It’s like magic. For stubborn areas, use the horse hair brush.
By Jon
So so
September 27, 2018
Not exactly as strong as the YouTube video made out to be. Seat they sprayed it on was 3 times in worst condition than mine and came clean but I get it and it’s no stronger than normal everyday cleaning solutions. Little disappointed but knew that what they say and what is is two different things.
By Jordy R.
Prairieville LA
More the merrier
September 26, 2018
Really works on stubborn mildew.
By Drew M.
Amazing Product, never used anything better
September 12, 2018
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!
By Jo
Sevierville Tn.
Jo Sevierville Tennessee
September 5, 2018
Absolutely love this product. Our boat seats are new again. We had tried everything but nothing worked. I googled to see if there was something that we hadn't tried and found a video of Marine 31. I ordered a bottle to see what it would do and we were amazed. Love! Love! Love this product.
ProsIt absolutely works!
By Kim
Annapolis, Md
Tried the 20oz; reordered the gallon
August 31, 2018
Best mildew remover I've ever used. Got it for my boat, use it also on deck furniture, shower tile, etc. The Best!

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