Jack there is a product available from Schucks auto parts, Kragen's etc for windows. It come is a black plastic squeeze bottle and youput it on a wet widow and scrub with a damp rag and rinse ti cleans of the spots and leaves a coating that helps to prevent spotting. The spots are caused by the manganese+(iron) in the water in combination with lime which is what helps to keep water sweet and soft and able to sheet off of surfaces. Too much manganese and iron and not enough lime give hardwater and spotting. vinegar is a base, not ionic or anionic, it will help some, but not a lot.
This stuff from Schucks really works, I am ouat right now otherwise would give you the name, I can't remember it to save my soul.
