cuz windex will not get them clean.
Vinegar or ammonia, Dawn, and water. Rinse well
I use vinegar, a car was sponge and newspaper.
I purchase a microfiber called SuperCloth that was well worth the investment (under $40/4). It produces a streak free shine on all glass, screens, and appliances.
Do not clean windows on a sunny day, it will produce a haze.
In there is a build up, use warm soapy water to scrub then wipe down and follow with wet microfiber.
Have you tried mixing 1 part vinegar to 1 part water then cleaning with newspaper instead of a cloth or paper towels? Many swear by it!
I have used soda water on crumpled up newspaper for hard to clean windows. Worked a treat. I also use methylated spirits on crumpled up newspaper.