I can’t say that washing windows is my favorite way to spend sunny spring afternoons, but thanks to my mom I do know how to make them shine! (And thanks to my children, I don’t stress when they are smudged up 10 minutes after I’ve tackled the job.)
Using an old gallon-sized bucket, I pour in about 1/2 cup vinegar and then fill the bucket 1/2 full of warm water. Using that solution I scrub the windows and then wipe them down with a crumpled sheet of newspaper. For smudge touch-ups, a vinegar/water solution in a spray bottle is quite handy.
Natural. Non-toxic. Very inexpensive. Recycling. Clean (for 10 minutes or so, anyway).