I know there is a company in So. Cal if I remember right that will do them. I don't remember their name right now but if you google license plate restoration they should pop up.
Sorry,
Mike
p.s. Mitch beat me to it. But that is the guy I was thinking of.
Check to see if your DMV will accept a restored plate for YOM registration. Some states won't. My guess is they can't tell a well restored plate from a reproduction.