Over the 4th my wife had new black dress that she just got and while sitting on our boat talking with friends for just a few minutes the black dye from the dress bled in to our white vinyl. After all these years of having white vinyl this never has happened us.

She did a search and come up with dish soap, white vinegar and warm water. We tried this and it helped a little but it's still there.

I am thinking an oxidizer may work but I don't want to cause more damage or worse, make it turn yellow.

Does anyone have suggestions that they know works?

I think I need to add "Naked Bodies Only" next to the "Naked Feet Only" sticker now!

Tilex. Wet the seat spray tilex scrub and rinse good. Don't let it streak dry or do in the sun. A lot of these stains will naturally disappear/fade if you leave your boat out in the sun. White upholstery is cool but hard to keep looking good. Good luck

Sunlight
What you didn't get out, will likely get bleached out by the sun. Many folks have posted such. It's painful to look at before it goes away, but the suns rays will probably bake it right out for you.

Had a similar situation last summer, benzoyl peroxide (zit cream), followed by a day of sunlight, followed by reapplying protectant.
I found out about the pimple cream via Internet search, apparently Barbie collectors use it to restore the dolls. Ya know, to get rid of that tramp stamp of Ken's name in olde english from spring break.

Exactly what he said. Had a Kool-Aid stain on one of my seats, I couldn't get it out even with a magic eraser (use as last resort on vinyl). After a few days in the sun, stain was gone.

sunlight, just let it do its thing

+1 ^^^

HEY...........We can not help without pics of the wife in this black dress!!!

She does understand that next time she'll have to board naked...doesn't she ?

Had the same thing but with a pink bathing suit. Sunlight took it right out.