Sorry never thought about it, but taking the bags and pipes off is easy and a must to gain access to the wheel. Brake side will bust you knuckles without brushes.
I used automotive aluminum wheel cleaner. Spray it on let it soak for a few minutes then I purchased a brush that looks like an oversized toothbrush and a baby bottle brush for cleaning the slots and hosed it off. Then wiped it with some clean rags wrapped around a sponge. If it is seriously oxidized you would have to drop the back tire to use a proper polisher on it.
Can you all believe I talked about cleaning something on the bike without saying the P word.