in a spray bottle, dilute all-purpose cleaner (meguiars or eagle one) with water at approx 1:4 and brush the solution to the mags. I use either a tooth brush or wheel brush. rinse after brushing.
B. Polishing:
I use a low speed/high torque rotary grinder with a flexible shaft fitted with a cotton cloth buffer. In buffing, I use a columbian compound (white rouge stone) to bring back the luster and mirror-finish of the wheel.
to protect the finish, i wax the wheel after buffing.