Glass is substantially harder than paint, so typically paint polishes and pads will only reduce them a very small amount. For visible scratches you do need a cerium oxide based product - to REALLY make any progress on that it also takes a bronze wool buffing pad (like steel wool, made out of bronze) and a rotary polisher.
I have some raw stuff here I've used to take key marks and things like that out of glass, but its a MASSIVE mess (flings a black oxidizer residue everywhere) and does take some comfort/skill with a rotary to do it.
The kit mentioned above is a good option if you need something for very light scratches thats a little more 'consumer friendly'. Its such a specialized product that we don't offer a solution at this time.