Yes, you can apply the WD40 to the surface of your alloy wheels. This particular solution is used to remove greases, oil or dirt and also prevent any traces of rust to damage the quality of your wheels. All you need to do is to wash off your alloy wheels with some amazing rim cleaner and let it dry. Apply WD40 on a piece of cloth and rub it all over the surface, in the affected area, and on the surface more exposed to dirt.