I cannot take credit for this discovery; however I can tell you that it works! In my opinion this is the best way for washing windows. A cleaning company shared this tip with me four years ago, I was using glass cleaner, vinegar and newspapers. Nothing I did completely cleaned the window. This is the only thing I use now.
Items Needed for Washing Windows
(All items except the Dawn were purchased at Dollar Tree)
Dawn Dish Detergent
Small Bowl or Bucket