If you are able to catch a nail on the scratch, it is unrepairable. Glass compaines might be able to polish/remove some of the scratches.

How did you aplly the glass polish? High speed rotary polisher will work best because of the heat it creates.

Works with your 4 1/2" or 5" air angle grinder set at 2000 rpm. WARNING: This System Removes Glass. Keep Glass Wet With Water and Spinning Abrasives Moving Across Entire Surface to Avoid Heat Build-Up and Optical Distortion. Includes: Self-adhering hook and loop pad, coarse, medium and fine abrasives, Pro Glass Polishing Kit (40011) and instructions.