Vinyl boat seats can develop stains from a number of sources: formation of mould and mildew, salt water left to dry on the seats, and fish blood, to name just a few. If the seats are not cleaned immediately after exposure, the liquids penetrate the vinyl and form ugly stains. Vinyl, like leather, is a porous material that absorbs any moisture that it comes in contact with. Removing stains from vinyl boat seats is not impossible, but care should be taken to ensure you do not damage the vinyl.
Remove the boat seats onto a concrete area if the seats are removable. If they are not removable, you may clean them inside the boat.
Mix two to three squirts of dish detergent in a bucket of water. Apply the soapy water to the boat seats with a large sponge. Allow the suds to remain on the seats for five minutes. This gives the soap time to soften and loosen stains from the vinyl.
Scrub the stains on the boat seats with a soft-bristled brush. Rub the brush gently against the vinyl and avoid scrubbing too hard, as you may damage the integrity of the vinyl.
Rinse the boat seats with a bucket of water or a garden hose. Be sure to remove all soapy residue from the vinyl.
Mix four parts water and one part ammonia in a bucket. Apply to any stains not removed from the vinyl. Scrub the stains with the soft-bristled brush until stains are removed. Rinse the boat seats with cool water.
Dry the boat seats with old towels. Dry the seats completely to avoid mould or mildew growth.
Spray a leather or vinyl conditioner onto the boat seats after drying. The conditioner softens and protects the vinyl surface. Spray conditioner onto the boat seat, leave on one to two minutes, then wipe off with a clean dry cloth.
Do not use abrasive cleaners or a steel wool pad on vinyl as you risk damaging the material.