Is there a way to get rain etching off of glass? (see details)?

I live in an old building with windows that are likely older than me. I was cleaning the pain that sits behind the screen the other day and found that I was unable to get it fully clean. They had cloudy marks on them that looked like the marks left behind by rain drops. Presumably, over the years the rain went through the screen, hit the glass and for some reason the acid in the rain etched the glass. I don’t have much hope of getting it off since it’s glass, but I thought I might ask because you never know.

so, anyone have any ideas, or is the solution to live with it? (I don’t own the building, so I’m not replacing any windows.)