While the windows could all be washed from the inside, that would leave the screens as they are, so instead we washed them all from the outside first. We used the Windex Outdoor. Listed at Home Depot as "32 fl oz Blue Bottle Outdoor Sprayer", $7.98
We ended up buying two bottles. The first bottle did the first 17 windows (four hours), then we had to go get another bottle to finish it off the remaining 13 windows (three hours), a week later.
We first sprayed each window down with just a jet of water as a pre-rinse. Then we used the Windex Outdoor to spray it down with a "soap" solution. We finished with another clear water rinse. This was done outside, using a garden hose for water, so it went thru the screens to the outside of the windows.
Then, after all the windows were rinsed, washed, and rinsed on the outside, I went inside and (a) cleaned the inside of the window, using regular Windex, and then opened each window up to wash the outside, again using regular Windex.
I tried using a squeegee, but it left streaks, so mainly cleaned the outside and dried them with old rags, wash clothes and diapers.
