When I'm at work and have to clean the wheel after replacing a CV I usually wipe off the really thick stuff with a shop rag, then use brake clean to get the grease off. I have found that if you wipe it off quickly then spray it down with Simple Green(to get the brake clean off) it has really good results and doesn't seem to damage the wheel. I don't know if you should use the brake clean on the polished face of the wheel though.