I was at a Car Detailing clinic at Detailer's Domain in NJ just this past weekend. Always purchased all my car detailing products from these guys.
The Adam's Deep Wheel Cleaner product they recommend is one of the best in the market.
Apply to the wheel while it is dry. Let it do the work for about 60 seconds, and use a Boar's hair brush to clean before hosing off with water.
Do one wheel at a time, all 3 steps.
Adam's Deep Wheel Cleaner
Boar's Hair Brush