If this gives you any indication, I have had a long scratch on my windshield for well over a year with no or minimal reduction in its appearance. The problem is that glass is much, much harder than paint and requires different compounds in order to work. As well, glass polishers will use felt pads with special polishers that supply lubricant in the form of water to the area being polished. In that context, it's easy to see why a polishing pad and a finishing polish are ineffective.
Here is how a professional glass polisher would remove a defect such as a deep scratch:
Yeah glass polishers usually are felt pads you put on a drill and using really hard abrasives and water. Scratch removal usually takes a long time too working the polisher.
Yeah glass polishers usually are felt pads you put on a drill and using really hard abrasives and water. Scratch removal usually takes a long time too working the polisher.