You can polish glass, but you have to know how to do it correctly. If you polish unevenly, you can cause a lensing effect which distorts your view. A good custom glass shop should be able to do it for you.

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1979 240D, 4spd manual, Power Sunroof, manual windows, 147k miles, Pastel gray/Black MB Tex.
1991 300D 2.5 - Smokes like it's on Crack!