In article ,
"Percival P. Cassidy" wrote:

Our porcelain-enamel kitchen sink has developed stains, especially where
the plastic "feet" of a "sink protector" have rested. I think that stuff
that has been dropped into the sink and not rinsed away immediately has
caught on those "feet" and remained there long enough to stain the
surface. I have cleaned the sink from time to time with Soft-Scrub, but
hat no longer seems effective, and now I find that the stained areas
actually feel rougher than the unstained areas.

Any suggestions how to fix this problem? Any way to seal the surface?

Perce

Hmmm... try some 'Bar Keepers Friend' on it... It's gotten out stains I
didn't think would ever come out. It's 'magic' ingredient is a little
Oxalic acid. I've had best results with the powder version, but then
again really don't have a lot of experience with their liquids.

http://www.barkeepersfriend.com/

A friend once had a slob in one of his apartments who let dishes,
cutlery and whatnot sit in a wet porcelain sink for years. There were
numerous deep dark rust stains & mineral deposits that looked hopeless.
The usual cleansers took off the the surface stuff, but only lightened
up the rust stains. BKF didn't remove them instantly... it took several
good scrub cycles, but the sink came out looking new.

Makes stainless look new as well.

Many super markets now carry it.

No affiliation... just a happy user. Good Luck, let us know how it comes
out.

Erik