[BlindHandyMan] Scratched Glass repair

[Betsy Whitney, Dolphin Press]

Aloha all,
My friend has one of those lamps with a large round magnifying glass 
in the center with a tube-like light that goes around the outside of 
the glass. Somehow she has managed to scratch the magnifying glass. 
Any ideas about smoothing out the scratch?
Thanks...
Betsy