If you have scratches in your glass windows you can take the scratch out, or at least make it less noticeable. Just rub regular toothpaste over the scratched area to make it less noticeable.
If you have a scratch in glass or in a window, you can make a mixture of dried mustard and vinegar. Use this thick paste and buff the area a few times. The scratch will lessen so you can't see it as much.