Good question on keeping the wheels clean. I tried to get mine 100% clean the other day, and already have some black spots on the inside flat surface of the rim. Probably some minor rock chips damage which then 'holds' the brake dust. Hence these black dots are very diificult to remove. I once heard you can use some sort of clay to get these spots off, but haven't tried that yet. The good thing is that these dots are only visible when you stick your nose almost through the rim spokes