[Rock-It Man]

Originally Posted by EJR8402

Try a clay bar first. If that doesn't work, try Wolfgang Perfekt Vision Glass Polish:

https://www.autogeek.net/dia-glasswork-restorer.html

It also works great on other glass around the house (like glass cook tops).

There's an idea! There are glass cooktop cleaners you can buy at the supermarket , which contain chalk, a gentle abrasive that doesn't scratch glass but removes hard water residue very well.

I live in a soft water area, so this is not a car washing problem for me, but I can vouch that these cleaners do not scratch glass cooktops, and do remove stubborn boil-off water spots.