re: washing car windows. What to use

The back glass in my new pickup had some sort of residue on the inside that wasn't removed at the factory. You could still see the marks left by the robot's suction cups. Tried a couple of different ways and couldn't cut that stuff. Bought a product from autogeek.com called DP Krystal Vision Glass Cleaner. It did the trick. Use a microfiber towel as suggested earlier.