We all know the stock brakes are very dusty and make a mess on the MINI wheels. WMW has found the Sonax wheel cleaner to be the easiest way to clean the wheels. But I'd love to see some others that have used it post their experiences in this thread. Sonax makes it so you don't have to scrub your wheels. Just spray it on, let it sit about 5 minutes and hose it off. If you still have any residue from having really dirty wheel, just wipe down with a light wipe.

Now if your not sure you want to commit to a large bottle, WMW has small trial sizes that is enough to do your wheels once that will let you give it a try.
http://waymotorworks.com/sonax-trial-size.html