Easy as pie with this:
http://www.i4detailing.co.uk/acatalog/E ... ush_1.html
Nicely cleans the full width of the rim and the back of the spokes through all the openings - just need a smaller brush for the whel nuts/holes. Lasts well too, if you were wondering about the price
Or if you are tight like me.
http://www.i4detailing.co.uk/acatalog/S ... ush_1.html