PugetSounder

It is mold growing in the vinyl. Mix baking soda with a little bleach into a paste and apply, let sit overnight, rinse and reapply as necessary. Be cautious of the bleach on the stiching. In my experience you can only treat it- you can never get rid of it completely, short of replacing the vinyl.

Bleach will harden the vinyl. Many upholstery in Seattle area do this. Then a couple years later the vinyl is trashed.

I have been getting pink spots on my white vinly seats... Any idea of why this is from and how to get it out. Conventional Cleaning methods seem useless. I am thinking its bacterial and coming from the inside.. I have ruled out it came off of anyone's bathing suits or clothing etc. They boat is newer being 2009

This stuff is specifically for pink stains caused by bacteria on vinyl. Get it from www.pink-away.com

Worked for me! Expensive, but works.