Yeah, I used to use a kitchen dish scratcher (not brillo), and that worked but not that well. This last time though, I used Mean Green All Purpose cleaner on the white letters, plus a swipe of a scratcher, and then hosed. They came out better than ever before, and this also worked wonders on a set of dirty whitewall tires on a 94' Buick Century I did. They went from brownish yellow to white again, quite quickly and easily.