sorry about your wreck, but those cages definitely work. With mine, I lightly sanded the scrapes and then shot some flat black rattle can on them, holding a piece of cardboard right behind to catch the overspray.
That is assuming they are black (which is not a horrible assumption, since probably 98% of them are).... When they are chrome, like mine, you are screwed (yep, it was a mistake, should have gone for painted). I guess if it happens to me, the silver steel would be a close match to the chrome and I would just coat it in something clear at that spot to prevent rust, or maybe some chrome-like touchup paint. :/