Wash the wheel with your hose to remove loose grime. Spray "easy off" oven cleaner on, allow it to soak for 20 minutes, then scrub the wheels with a teflon safe dish scrubber. Wash off all cleaner, then if pitting is still visible...sand with 400 grit sandpaper wet until pitting is gone. Then clean with water, dry with Terry cloth. Use Aluminum brite to bring the shine back. I like to polish with my buffer, then hand polish leaving a coat of polish for protection from oxidation.