I would say to prevent it in the future, do not use any harsh wheel cleaners, as they have a tendency to remove coatings on calipers and rotor hats. My car had Rotora BBKs with ceramic rotors for a while while it was on the car show circuit, and now for street driving it has steel rotors with the aluminum hub. I don't use wheel cleaners at all, and I have no deterioration of the finish on them at all. Now, the disc itself will get a little orange after washing the car if it sits, but it quickly rubs off with a brake application. If that is what you are trying to prevent, then good luck with that while you have steel rotors.