Just used Eagle One Etching Mag Cleaner for the first time last week, which is an acid-based cleaner similar to Meguiar's Wheel Brightener, but readily available and cheap ($5 on Amazon). Sprayed on, brake dust started to run on its own, agitated with a soft brush on the face/spokes, and a wheel brush in the drums. Wheels had never been so clean, at least until I drove it again! I made sure to rinse really well, so no acid was left on the clear coat. Fast and effective. Really made short work of the dust & grime baked on to the wheels.