Auto body repair & detailing: Windshield Cleaning, mirror glaze, mike gallagher

Question
What is the best way to remove years of water stains on windshields?  During our last rain - we do not get many in LA - I drove my brother to the airport at night and the glare from oncoming vehicles made it almost impossible to see-scared me.  A friend suggested Bon-Ami and a soft cloth but I wanted a second opinion from more of an expert.  I also know there are additives to the windshield cleaner tank that reduce or eliminate water beading which would help, I think? Right now, I feel I am looking through a shower door which has never been washed.  Cars in question are 14 and 12 years old.  Thanks for any advice you can provide.  John

Answer
I would be afraid to use Bon-Ami but I have heard of some people using toothpaste,it would be less abrasive. I recommend using Mequiar's Mirror Glaze clear plastic cleaner (part#1708) and Mequiar's Mirror Glaze clear plastic polish (part #1008).

                                Mike Gallagher
                                Gallagher Holdings
                                Paint World
                                1-800-548-4321