I used ettore, it takes a little elbow grease but wont scratch the glass, made my glass look like brand new againSteel wool is my window cleaner. Never clay barred windows.
https://www.homedepot.com/p/Ettore-...h5LS-YklQEt5iuHxzlhoCzlsQAvD_BwE&gclsrc=aw.ds