Car glass scratches if formed on wind shield by dry or defective wiper or any sharp objects can not be removed.Similarly any scratches on the side glass windows due to excessive wear cannot be repaired.
Cracks on the wind shield can be repaired and they are different from scratches.Also scratches /pittings on head lights due to sand,and dull hazy appearance on acrylic light clusters can be rebuffed and polished.As pointed in earlier post,Midmac flyover to Qatar decoration round about take a U turn and turn right at Tayseer petrol station,Glass is the name of the shop.
(Entrance to tayseer is very tricky since road works are ongoing ,very easy to miss your target.Good Luck.