I have several scratches on my inside windshield. I am using Turtle Wax Rubbing Compounds (two types, heavy duty(red) and then more fine compound (white). Use the red first (use a soft lint free terry cloth) and rub away. Once you can't really feel the scratch with your nail(finger) switch over to the finer compound. Only started doing this, and so far I have reduced the depth (wasn't extremely deep, but I did notice a difference)of the scratch. Try that, it shouldn't scratch your window any further. But do use caution.