I put a vinyl decal on the back of the rear window and now it is peeling off. I have a replacement but wanted to make sure I didn't mess up the glass when removing it. It is on the outside of the rear window. Can I just use a flat razor to scrape it off or should I use some type of chemical. I don't want to scratch the glass or destroy the tint. Is the tint on the inside of the glass or the outside? Any suggestions for removal would be greatly appreciated. I guess I didn't get all that zaino off the glass very well and that made it peel up after a bit.