As someone with possibly the worst wheel design by BMW to clean, I know your pain. I have an e30 92 bmw 325ic with the classic basket wheels by BBS. Them suckers have so many nooks and cranys to scrub it is virtually impossible to clean them entirely. I have tried those power balls, but find they are too large to get in the areas that need the most cleaning. I have tried every kind of wheel cleaner, including a few of my own recepies, but no success. I find ceramic brakes, and frequent elbow grease is all you can really do. I sit there for a minimum of 3 minutes per wheel with my index finger jaming a terry cloth arround each spoke until it looks decent. I swear, if i werent into origionality, and those wheels didn't look so fantastic on the car they would be gone!