frost free windshield

I read about this in a magazine. If you live in an area where the winters are cold and you do not have a garage to keep your car in this tip is for you! To keep your windshield, side windows and mirrors from frosting over, keep a spray bottle of rubbing alcohol in your car. When you park your car for the night spray the windshield, side windows and mirrors with the alcohol. There will be no frost to scrape in the morning! This works well in the mountains of central Pennsylvania but I don't know how well it will work in colder areas.