Hi Shirley: Try this site, it has loads of tips: https://www.familyhandyman.com/windows/how-to-wash-windows/
My husband uses windex window cleaner that hooks to the garden hose. He leaves the screens in and they get clean too. He's been using it for years.
I just saw a product that consists of two pieces. You put one piece on the outside of the window and the other inside. It's magnetic so you wash the outside by moving the piece on the inside. Looked as if it might work, without hanging out of the window!
here are many tools that will help https://www.google.com/search?q=window+washing+tools+from+highrise&safe=active&sa=X&rlz=1C1CHBF_enUS750US750&tbm=shop&tbs=vw:g&ved=0ahUKEwiu_uvm8NPhAhWCITQIHXlJBRMQvQ0IzgI&biw=1366&bih=657