Hello Simon,
I use to spray Meguiars stuff on the wheel, than brush off with an old dishbrush and after that rinse it off with water, though not use a compressor and dry it off with a fiber cloth.
After that I take the wheel into the garage and use a toothbrush and a liitle more Meguiars stuff and clean the hard parts. When the wheel is completely clean I use another Meguiars foam and polish (do not remember the exact name of it at the moment as I am not in my garage) the wheel which also has a protecting effect. I clean the wheels thoroughly once a year on both sides. Can be done during the off season so you still can be close to your MOG. I know it is hard work, but when not in a hurry, so what!
Ken in Sweden
