or a wheel buff with a corded drill and a pretty aggressive polish like SSR2.5 or 1ZPP, then when i've gotten the fine scratches out I hit it one last time with mother billet polish. I just traded in the truck that had the polished 18's on it and now i'm getting chrome, those polished aluminum were just to much work, but man did they look good when it was done.
I found the mothers powerball or flitz ball worked great with the billet polish for the final polish but didn't work so well for getting those fine scratches out.