Are the wheels clearcoated? My wheel cleaner of choice is Eagle One A2Z. Make sure you use it in the shade on cool wheels. Also, S100 Gel Wheel Cleaner (from a Harley shop) may be good because it kinda clings to the wheel. You can let it sit for an hour or so to really let it work. Completely safe for the wheels. You could also try a claybar. Maybe a good paint cleaner/polish.
Believe it or not, I've read that NuFinish can serve as a good dust cleaner because of the strong cleaners it contains. Perhaps the only good use for it
You can also try brake parts cleaner. Spray some on a soft rag, not directly on to the wheel. Make sure you rinse it well.
If the brake dust has been on for a while, it is possible that the clearcoat has been pitted.
If the wheels aren't clearcoated, I can probably recommend a few products to try. I'm not too keen on the idea of using Simple Green on the wheels. Especially on bare aluminum wheels.
