dont hit it with a wire brush!! u will scratch the crap out of it!! your better off to hit it with some paint stripper, then sand it with some wet n dry.

u want them looking new but u dont want to paint them? it will take you all of half an hour to prep and paint them!.
if u want the writing a different colour, paint the letters 1st, then let it dry, then place masking tape over the letters, then get a stanley knife blade and cut around the letter edges, once done, spray the rest of the rocker cover, then peel the tape off the letters,
it will be worth it and it will look sick!