Not sure what brake pads people use, but Ive sort of resolved to not buy wheel cleaner again.
For everything from high bite-high dust euro pads to the cleanest ceramics, the residues generally come right off. On the euro pads, the dust cleans off super-easy, but there can be some small bits of black dirt embedded. Ive not found any cleaner to be particularly effective.
Ive run the color changing stuff, and it too doesn't do much. It will change color near the caliper, as will overspray on the disc, but the dust on the wheel? Not much of anything.
Ive taken to using wheel woolies, which work great most of the time, and I use soap from the bucket. I rinse my tools constantly, so the soap bucket stays clean and grit free.
Sometimes Ive used meguiars wash and wax (waterless wash, it's a white translucent product) on the wheels, as I figure the waterless wash (though I'm not using it that way) helps lift and lubricate particles, and the wax helps protect/seal the surface. If Im going to spray the car with HydrO2, then the wheels just get soapy water from the bucket, but get that treatment along with the rest of the car.