You can nearly always get rotors clean again. I like to lightly sand them with some fine sandpaper and then wipe down with isopropinol and a CLEAN cloth (preferably a disposable shop cloth). Pads can be cleaned if they're very lightly contaminated--generally sanding is the best course of action. You can try drenching them in alcohol and blasting them with a propane torch also. But they're porous and if they're really contaminated they really just need to be replaced.