On Sep 5, 10:51*pm, Artful Dodger wrote:
My vinyl? some kind of not porcelain ? *bathtub has a nasty blackish
stain on the narrow front ledge just under the faucets. *I have
applied mildewcide several times. *Also applied bleach. *Also tried
SofScrub. *Nada.

I don't know what the stain could be from.

Is there anything else I can try?

I would guess you have a fiberglass tub and you might try one of
the products make just for that. Keep in mind that it may not be
removable and that using the wrong products on it can damage the
finish making matters worse. However I would guess the products you
have used should normally be fiberglass safe.