JC220 (1 Week Ago)
I've done it on windshields. Patience, grasshopper. It's a slooow process but it does work.
Rule of thumb is if you can feel it with your fingernail it's too deep, but that probably doesn't apply to lights as they are more prone to pits than scratches.
If you are using the powder keep the slurry fairly thick.
1993 500E Signal Red/Parchment
1987 300TDT Ivory/Palomino
1995 E320 Cabrio Black/Parchment
1969 280SL Silver/Green - 1970 280SL Black/Parchmen
1987 560SL Signal Red/Palomino
I did try it and it is a waste of time IMHO. It will eventually work after hours of polishing... I always buy new lenses if affordable or give these to the shop that deals with glass - they have special tools that allow to polish the surface properly. If you decide to it - take my advice and don't overheat the glass, it will break. Ask me how I know about this...
1992 500E Porsche type 2758
1988 Porsche 944 Turbo S