I have a magnesium front sprocket cover from a motorocycle that I have begun polishing.

I have it all stripped of paint and have begun polishing it.

On a small test area it started polishing really well with the black emery, brown tripoli and red rouge that I have. The problem is with the final compound.

Since magnesium is so soft the white diamond compound still leaves noticable scratches, even with a loose cotton wheel!

Is there a better compound to use for magnesium or should I try some different method?