Basically it comes down to sanding and buffing. If you Google "fixing curb rash" you can find some good tutorials on fixing such problems. I just picked up a set of used 18's for my daily driver which have some rash on them, and bookmarked a few sites (haven't got access to them right now, sorry) I found by doing the same thing. They're not polished but I still have to do do some work to 'em so they look new again. Anyway after you sand the metal smooth and buff it up to be shiny, the tricky part may be putting clearcoat on it again without messing up anything else. I'm not sure of a good clearcoat to use, but maybe if you find one of those tutorials I mentioned they will recommend a product or two.
