there are few acids out there that work perfect w/o damagin the clear coat on your wheel.. we had this when i was a lot tech where i sale now... i shined some pretty digusting wheels.. it really helps in wheels that have spaces that fingers wont go (buick)...

then after you rinse, use ammonia-free glass cleaner all over it and wipe it all off.. you could also look into some aluminum polish for silver and chrome wheels