Most shallow marks can be polished out. I'm not an expert but I have seen it done. I can't tell you the exact grit of abrasive that was used but it was done in several steps with each step being a finer grit paper/polish. I can caution you to not concentrate just on a small area or you'll get a distortion like a fun house mirror effect from "cupping" the glass.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.