you will have to use a brand new razor blade scraper, wet the window first, look up a scratch waiver first incase you leave a scratch or two but you shouldent if you are carefull and only go up and down, also i heard on here of someone using brillo pads once, they said they dont scratch glass, but i am not sure on this so you better look it up, it will take you forever, so do it in a day with nothing else and charge 3 - 4 times the pruce of the house