i just got some crabs like that and i used one of those rust removing wheels for a drill and used it around the outer rim of the wheel. You need to be careful on the face of the wheel which is a little rougher because it will scratch easy with that wheel. Try finding a finer disc to sand it with.or maybe just use an airplane stripper? i ground mine down then washed them and used duplicolor graphite color rim paint and then used the same brand rim paint clear coat. the graphite is pretty dark but looks nice on my van. 2-3 coats of each looks nice. autozone has some brand of rim paint but is expensive. i got this stuff from meijers for about 3.50 a can. one can of graphite and one can of clear and we were good to go.hope this helps