After trying everything from water/alcohol/ammonia to Windex and all the rest (just about). This, I have found IMO, works the best. Spray it on and wipe off with a cotton towel. It really cleans the glass the first time, with no streaks. Exception, due to heavy use this winter of the rear defogger (safe to use on) I had to go it over twice. It is my understanding that it has 2 or 3 different alcohols in it. It comes in an aerosol or squirt bottle. Also it is a bit pricey compared to household glass cleaners. But it gets the glass invisibly clean.