Left side shows hard water spots and right side shows window after using white vinegar.
This has been a very hot dry year in Wisconsin and since I added a lot of new plants this year, I have been watering a lot. Since our suburb does not have city water, we use a private well that has hard water.
When I water the yard, I carefully set up my sprinkler to water the plants and not the house. It usually works just fine, except when the water pressure becomes uneven and causes the spray to surge higher and water the windows. When the water dries, it leaves ugly white spots on the windows and those spots are very difficult to remove.
Yesterday, I went out to wash the windows once again to remove the white spots. First I used Windex which cleaned everything off the windows but left the spots behind. Next I tried Magic Eraser which usually cleans everything. No luck, when the windows dried, the spots were still there. Finally I tried straight ammonia on one window and white vinegar on the second window. Surprisingly both of these humble cleaners took off the white spots that the commercial cleaners left behind. The biggest surprise to me was that simple white vinegar costing 99 cents at the grocery store worked best, taking off all the white spots with very little scrubbing.
Best of all I was actually “going green” using just vinegar, not some toxic solution of chemicals.