Below are the steps which will guide you how to remove window frosting spray: 1  The glass needs to be sprayed with glass cleaner. 2  This will help in lubricating the glass surface so that you don’t have to scratch the glass.3  Scrape it off with a sharp razor blade that is held at about 15-degree angle to the glass.elow are the steps which will guide you how to remove window frosting spray: 1  The glass needs to be sprayed with glass cleaner. 2  This will help in lubricating the glass surface so that you don’t have to scratch the glass.