Ethan is right that you should only use products which you could safely use on your paint, since MB wheels ARE painted and clear coated, by and large.

I am glad it worked out for him, but personally I would NOT recommend use of rubbing compound on wheels or paint since it will take off the clear coat. Repeated applications of P21S, or clay, will eventually get that darned brake rash off. Just be patient and persevere.

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Steve
'93 400E