As the mini is really bad for brake dust welding itself to the lacquer on the front wheels, I found the following made a huge difference and now I clean them once a week rather than twice.
Clean using water and meguiars shampoo only, no wheel cleaner. Dry off wheel and apply BMW mini liquid wax ( this stuff is like water ) allow to dry then buff to a high shine. Now use Autoglym wheel wax spray. Spray evenly over alloy and leave to dry, no need to polish.
No need to use the BMW wax each time, but use 2 coats of the Autoglym spray stuff. This makes it a very quick and easy task.
J.