Get some Wheel Woolies
. Seriously - they make cleaning ZCPs very easy. The long brush easily reaches the back of the barrel and the small brushes clean up the spokes and the edges behind the spokes. I use car wash soap to clean the wheels. Takes about 3-5 min per wheel.
Also - I use a blower to dry off the car, including the wheels. I finish it off with Armor All protectant.
Driving it around to dry the car is just asking to get road dirt thrown up on the wet surface. Not ideal.
1993 e36 325i, 1999 e46 328i, 2005 ap2 s2000, 2007 WRX STi, 2008 g37s coupe, 2009 Audi a4 2.0T Avant