"It's hard to get clean in HARD water... and We're in a Hard water town." I found this fact to be distrubingly true as I tried to clean my windows this past weekend. Since our sprinklers had not been adjusted since installation, our windows were hit and covered in dried on, hard, irrigation water. I took out my washer, and it did nothing! Frustrated, I went to GOOGLE, where all the problems can be solved, and discovered that Hard Water won't just wash off with normal soap. ( I knew that after cleaning my showers, etc, but I guess that I didn't equate my sprinkler irrigation water with Hard, cullinary water. HUGE DUH moment.)
Anyway, I read that with a little elbow grease and a vinegar/water mixture the stains should come right off... and did they ever! I am so pleased with my sparkling windows! I got to enjoy them for about 10 minutes too because we FINALLY got some much needed rain right after I washed them. Murphey's Law!