DONT use regular car wax on the windshield to clean it, etc, it will create a BLINDING glare for the driver of your vehicle, (similar to driving into the setting sun). I usually wet a cloth and use this to wet the w/s while cool, take a paint scraper and gently scrape the entire w/s , this usually removes all the water spots and any bug residue, etc., then clean the w/s 2x, then apply rain x. make; sure you get all the streaks removed or they'll be there under the rain x.