How do I safely get rid of hard water stains off of auto glass and paint without damaging either?

By far the safest thing for your paint is a product called Iron-Out. I've used plenty of times on both industrial and residential scales, all types of paints and finishes. The stuff is a godsend.

Take it to a high pressure laser (no touch) car wash as soon as possible. It will take care of the water spots without those scary cloth things going all over your car and wrecking havoc on the paint job.

2 products I know of should work (both at Wal-Mart)

The Works

or CLR Clear.

Good luck!

more than likely these stains are from acid rain and have etched into your clearcoat over your paint, they will not come out unless you repaint the car, and they won't come out of the glass either, a very common problem.

Ah.... the secret is vinegar..... living in germany for 4 years....with hard water I was told the secret..... mix vinegar with glassplus and you will be good.

Get yourself a clay bar. You can also use chrome polish on your window.

CLR and warm water. good luck