Polishing scratches, out of the outside, on window glass...

there is a process involving a special compound and buffer, cerium oxide or something like that. If you can feel the scratch with a finger nail, it will take a very long time to remove it and that will leave a low place in the glass surface/thickness. View gets distorted sort of like fun house mirrors. OK for any except the windshield with deep pitting and/or wiper scratches.