When ammonia isn't enough - how do you clean a windshield?

I just bought a car from a guy in sacramento, and the glass on the outside of the car has a lot of set in water stains from either a sprinkler or rain. I’ve tried glass cleaner, 50% ammonia/water blend, and straight ammonia, and nothing will get those stains off. A google search revealed several miracle cleaner products, but I would assume that there has to be another way. Any ideas? How about bleach or something else from the acidic camp?

Nitpick: Bleach is a base.

Now that I feel like I have to have some helpful input, I would suggest getting some mineral remover if you think the stain is just minerals that stayed behind when the drops of water evaporated. Of course, you would want to test a small area first in case your chemical etches glass or anything. As I have stains I can’t get off my windshield myself, I would also reccomend you wait for a more informed solution before trying mine.

If it’s mineral stains, vinegar should do the trick, and it won’t etch glass.

steel wool

I’ll second B&J’s recomendation of steel wool. My last car was purchased from a local chemical plant and had spent a long time parked near some cooling tower things that spew steam and some other crud into the air constantly. The windshield was so blurry that I didn’t feel confident driving until I cleaned it up. The stuff had built up like a mineral deposit and made the glass look very frosted. I started with Windex, tried vinegar, and CLR and Lime-Away. I finally had success with SOS pads.

I would just suggest only rubbing one way (up and down) and don’t get carried away. Should be alright.

Good Luck!

There are glass polish compounds (Amway makes a glass & chrome polish/cleaner) that work great.

The thing to remember, after you get your windscreen REALLY clean, and it will be after you remove the water spots, you’ll want to apply RainX or a similar compound.

Very fine steel wool, (like #0000 if you can find it easily enough) is great for cleaining glass. And as B&I said, (although I hate agreeing with him ;)), it won’t scratch.

There are glass cleaners with fine abrasives available at the auto supply stores. Check there. I’ve not tried it on windscreens, but the cleaner used for glass stovetops works well for glass shower doors.

Razor blade. Won’t scratch and will get just about anything off.

Bon Ami.

“Bon Ami” to you too!

It actually is the best thing I’ve found for cleaning windshields on old cars with lots of hard water stains, fog, etc.

This isn’t the first time I’ve heard someone recommend the old-fashioned Bon Ami (powder or cake - it’s a very, very fine and gentle abrasive, basically). But I’ve never been able to find any in the store. Where do you buy the stuff?

I’ve tried the spray-can version, but it doesn’t seem to be much different from Windex.

“CLR” removes Calcium, Lime, and Rust stains. In most grocery and all hardware stores.

For paint-related stains, like scrapes from a busted wiper blade, use naphtha, a cheap solvent in harware stores.

Autosol or Autochrome, very fine abrasive paste. I polished out some very bad scratches and removed some horrendous gunk from an old Volvo windscreen with it, was either that or a new screen, worked A1.