I bought this thinking that it would be good to avoid streaks/residue, but assumed that I would probably end up needing glass cleaner anyway. The first thing I tried this on was the inside of my car's windshield, which admittedly has probably been cleaned once... three years ago.. I was shocked that with minimal scrubbing with just the water-wet cloth all the gross stuff was lifted and when wiped with the dry part of the cloth there were absolutely no streaks. I did not end up needing glass cleaner, which is particularly awesome in the confined space of a sedan. I rinsed the cloth with water and hung it to dry, and afterwards it worked just as well on my mirrors. I'm so pleasantly surprised to get a product that actually did everything claimed in the ads. It's totally worth the purchase.