I have a USC sticker on my back windshield and I looked up different ways of removing it. Some sites say removing it with a knife is best but that just sounds scary. Dont want to scratch the window....Others places recommand to use a hair dryer and slowly peel it off. What are you suggestions on this?

 

A blade works well however since you are removing from the rear window you can't use a blade because it will perminantly damage defroster grid. Saturate well with WD40 and that should loosen it enough to peel off. If it is bonded so tightly that you are not able to peel off use steel wool (plain not an SOS pad) and gently scrub horizontally across the sticker.

To remove the reminants from the sticker spray WD40 on a paper towel and finish cleaning with cicrular passes over the area where the sticker glue is left behind.

 

There's a product called undo that works wonders! Google it to get more info. It's usually available in art stores just let it soak very well and only use the blade on glass not your vehicle's exterior! Good luck