I searched for this topic and found a thread that was 4 years old regarding the same situation. When I bought the car, it had spots all over the windows and still does today. No soap, clay, or compound can get rid of this. Could anyone recommend to me a product that would take the acid rain spots off of my windows? It's attacked all 10 pieces of glass on my car (including side mirrors).

Thanks!

A long time ago I did window cleaning for an industrial service.
When we had water staining on glass we used PUMICE.
You should be able to find it at a janitorial supply outlet.
It is a granular abrasive, so I would test it in an inconspicuous spot, but I think this might make a difference for you.
Remember that most staining is the result of impurities in the water such as lime leaving hardened deposits on the surface of the glass. Acid rain actually etches the glass, much like engraving, there may be nothing to remove. You may end up replacing the worst damaged pieces.
The best of luck to you.

I just did a search for "hard water spots" and came up with 18 previous threads, most with solutions. Oh, that's clever.

You say your issue though is acid rain spots, which technically have etched into your window glass. If this is the case, you'll have fewer options: replace glass or polish with cerium oxide. (do a search for this also).

I'd try the options for hard water spots first just in case your spotting is the result of hard water.

-John C.

I had the same problem with a car I bought out of Cali last week. The spots were so bad you could barely see out. I went to a local store called Knipps in Wichita Ks and bought a bottle of Spot Not and some 000 steel wool. This is what the instructions said to do. pour a little on the steel wool and scrub the glass and rinse the area immediatly with water It took me 4hrs to get my glass clean but it worked and it cost me 15.00 and 4hrs of my time. The spot not had a knipps label on it so I dont know if it would be available anywhere else. The previous owner of my car said it was one of the reasons he sold the car because he didnt want to shell out the money for all new glass. Hope this helps

Vinegar and water mixture on a towel and let the soaked towel sit on the glass for 2 minutes or so... it'll come right off.

Silverbeam taught me this gem.

I agree vinegar and water will work on minor cases of hard water spots, but if you hava a car exposed to acid rain, then the spot not is the way to go.

...some 000 steel wool.
I believe you mean 0000 which is superfine steel wool. I completely agree with you otherwise, My 96 maxima had the WORST hardwater spots on the back window and it was near impossible to see at night.
I actually used castrol superclean (I use it for everything) and the steel wool and with a little bit of elbow grease, my rear window was spotless.

www.eastwood.com search for glass polish. or scratch repair kit.