Originally Posted By: chrome
Glass isn't the easiest thing to polish, especially if you are trying to correct pitting. Cerium oxide will work with a rotary polisher to remove lighter scratches, but pitting will require a fair bit of skill and effort.
Probably better to consider replacing the windscreen.
I tried Cerium Oxide a long time ago on a windscreen that saw a good bit of acid rain in Hawaii, and it didn't help one bit. At best, it will work for very light scratches in glass. It's actually better for cleaning up bug and bird residue that is baked on the glass.