ive always used Nu-glass from napa auto parts. like a wax for glass. hard water spots may take a couple of times to remove them but this product is great. used for 15 years

 

I would like to thank you for pointing me in this direction. I have had a terrible problem with hard water stains on my automotive glass (5 months ago i moved to an area where the only water available is borehole water). The stains had gotten so bad that i was actually contemplating replacing the front and back windscreens of my vehicle. Which is a big deal here in Kenya and very expensive. Basically it was getting difficult to see outside at night when another car approached either from the front or the back. I had tried everything from vinegar to hydrochloric acid to steel wool and everything in between. Frankly i was not expecting it to work since i had even tried "guaranteed" products like CLR and other expensive cleaners. Bar Keepers Friend is not available in Kenya so i had to buy it off eBay, it took 6 weeks to get to Nairobi but it was well worth the wait. I made a paste of it as you suggested and in 30 minutes i was able to solve a problem that had me stressed for more than four months. I'm ordering a dozen cans to keep on hand! Once again i cannot thank you enough!

 

Cerama Bryte ceramic cook top cleaner does an excellent job at removing hard water stains from automotive glass. Use with a terry cloth pad on a buffing machine.

Cerama Bryte

 

I have used a couple products from CR Laurence with great success. The one iin particular is very easy to use and you can rinse it off. I will get the exact name and part numbers when the website straightens out. From my experience, it seems like some glass forms a "skin" on it, especially windshields, and water attacks or eats into it and etches the "skin". You can also feel the "skin" because when you wash the windshield, you , or at least I, feel a difference when I wipe from the area where the wipers pass to where they don't pass. The area where they don't pass seems to be grittier or rougher. Just my observation. ut the CRL stuff works great.

 

I was recently introduced to Ducky Products 'Water Spot Remover for Glass', they have several water spot removal product depending on the severity, this product is no joke. Did a side-by-side comparison to Mothers and this stuff ran circles around mothers. I was able to get spots off that have been on my glass widows for years. I also started using their Quick Clean & Wax product...awesome stuff.

 

Live with well water as well not sure how hard your water is but I just use a foam window cleaner with newspaper rather than a towel. Perfect every time.

 

How about those blue shop towels - ya know...rolls you buy in the six pack.

Are they as bad as paper towels in terms of scratching?

That what I've been using for my new truck glass along with some foamy glass cleaner?

 

CLR work great for my wive's car after being parked next to sprinklers in Blyth Ca. terrible water there.

 

I detailed cars in Florida for dealerships for many years. The water where i lived was extemely hard. I've done a few that people left a car near a sprinkler for weeks and the windows looked like shower glass, you couldn't even see through them. I'll tell you how to get it completely off, but you need to use extreme caution as its easy to screw the car up if you are not careful. You need acid wheel cleaner. Professional detailers use this and would prob sell you a bottle. Make sure its diluted, its very strong. You need to get a hard bug sponge, the ones we used were called bug blocks and were yellow. The whole time you are doing this its very important to keep rinsing the car off. Spray the acid on the wet window and scrub with the bug block, again keep rinsing.. also DO NOT put acid on the windshield. Windshields have some kind of coating on them and they will fog up permanently. So rinse, mist acid scrub rinse. Its takes a long time but works. The acid will not hurt your paint unless it gets left on it. I used to acid wash vehicles also.