[ptschafer]

I have found several OTC aerosol foams that work wonders. Ironically, I bought a cheap can of "Tough Stuff" at the dollar store, and it worked just as well as most other OTC glass cleaners I have tried.

I personally find it is not always the brand or type of product used, but the method of how you use it. Personally, I like to spray foam, scrub and wipe with a microfiber cloth, then re-apply foam again, and squeegee it off. Final step after squeegee is to take a dry MF and go over the dry glass with it to remove any final residue.

For those who are condifident with it, I use very fine steel wool with liquid cleaner to get rid of stubborn spots, or minor scratches and "buff" the glass to an ultimate shine afterwards.