I tried so many combinations of window cleaner, towel, microfiber, and technique and have made a breakthrough. Here's the best combination of product and technique I've found:
Product:
1. Stoner' Invisible Glass
2. Cobra Glass Cleaning Microfiber towels (http://www.autogeek.net/ww1627.html). The waffle texture, for reasons I don't understand, cleans glass significantly better than non-textured mf's.
Technique:
1. Spray window cleaner on window
2. Wipe off window cleaner in a circular motion with medium pressure
3. Mist a small amount of window cleaner on window
4. Wipe off window cleaner in a circular motion with light pressure
NO streaks. The cleanest windows I've ever seen.
I'm a skeptic about product, and have always preached technique, but this product combination is superior and--I believe--necessary to any serious detailer.
Product:
1. Stoner' Invisible Glass
2. Cobra Glass Cleaning Microfiber towels (http://www.autogeek.net/ww1627.html). The waffle texture, for reasons I don't understand, cleans glass significantly better than non-textured mf's.
Technique:
1. Spray window cleaner on window
2. Wipe off window cleaner in a circular motion with medium pressure
3. Mist a small amount of window cleaner on window
4. Wipe off window cleaner in a circular motion with light pressure
NO streaks. The cleanest windows I've ever seen.

I'm a skeptic about product, and have always preached technique, but this product combination is superior and--I believe--necessary to any serious detailer.