Tilex. Then rinse, but don't use ArmorAll afterwards. Get Meguiars rubber and vinyl #57 (RV and Marine)
One of the best fabrics for boat seats is a seat vinyl that is UV and mildew resistant. It comes in many colors. You could also use furniture weight Sunbrella fabric to cover cushions on your boat and it comes in solids and stripes. You can find both options at http://greatlakesskipper.com/category-1/14-boat-upholstery.html or http://www.beaconfabric.com/cat210.htm. Vinyl works well and is affordable and waterproof. Both Sunbrella and Valtekz make quality fabric for boat seats and have online sites for ordering.
simple green or castrol purple power cleaner
Use a flexible vinyl cement. RH Products HH 66.
use very fine steal wool and a color safe bleach i was told about it from an upholster i knew and it worked great good luck This worked for me: Go to mdramazon.com and find their Mildew Stain Away. You spray it on. Brush. Spray some more. Brush. and the vinyl looks like new.
According to this forum, http://forums.iboats.com/showthread.php?t=295220, Clorox Cleanup is a good solution for black marks on boat seats. The black marks are most likely mildew and will come off easily with Clorox Cleanup without damaging your seats.
The best place to find great cushions is at Pier 1. If that doesn't float your boat, you can always go to your local fabric store and make custom pillows of your choosing.
Use Elmer's Spray Contact Cement.
Tilex. Then rinse, but don't use ArmorAll afterwards. Get Meguiars rubber and vinyl #57 (RV and Marine)I own 4 boats and I have finally found something that EASILY cleans mold and mildew off of vinyl boat seats without stressing the material. It is called Double Duty Velour and Interior cleaner. It is mixed and made by a small company in central Il. called Huelsmann Distribution 800-359-7445. Besides cleaning the mold IN ONE WIPE!, it seems to minimize the amount of mold that grows back and conditions the vinyl. It is made for professional detailers and doesn't have any bleach. It is made of butoxyethanol, tetrasodium EDTA, cetyl dimethyl amine oxide and liquefied petroleum gas. After using it once, I bought a case (12 cans) for about $60, but they also sell half cases. This stuff is the simplest and best product that I have ever seen for this application…..an no I don't work for them…after wasting so much time and energy fighting mold, I feel compelled to share.
Most boat seats are made of cloth, vinyl or plastic. Since there are many different kinds of boats there are many different kinds of boat seats. Overton's has a website with additional information on boat seats.
Mr. Clean magic erasers work great, they sell them at Wal-Mart and places like that.
scrapping them off
I think this is a very straight forward method to clean your boat seats when they were wet, use soap and water and clean in between seats. Here is the site for more information. http://www.ehow.com/how_6626367_clean-boat-seats.html