Water spots are from lime scale in hard water.
Try vinegar windex or similar to remove those lime scale water spots

 

Repairman - it's more then water spots, it almost looks like dirt or smear or almost like there's dirt coming off the cloth in the car wash tunnel while i'm half way through the tunnel, its hard to explain but it's definitely not just the water spots, even when i dry the window and i use sprayway glass cleaner and then use spray wax it STILL has streaks / spots its a pain in my A**..

 

Use a chamois cloth to dry the car after a good wash. If there's still water spots, it might be time to wax the car. I started losing luster/getting spots in the red jewel metallic paint and waxing made all the difference.

 

nerd it's not my car that I'm talking about I'm talking about my back window.

 

If it's the outside of the window, clean it with any good method then use RainX water and rain repellent. Read the instructions, or follow my method:
1. Wash and thoroughly dry entire window
2. Fold a single paper towel into a quarter-sheet
3. Spray RainX onto 1/2 of window
4. Use towel to spread it around, making sure that if there are any beads still apparent to keep "polishing" (not really, but that's what it feels like) until you have a haze
5. Repeat on 2nd half of window
6. While that sets up prepare the remainder of your paper towels
6a. You'll 2 of: 3 sections of towel folded into a single quarter
6b. 2 sections of towel folded into a single quarter
7. Get a very large cup of water, or a bottle, or a hose/sprayer, then on the 1st half, start at the top of the window and pour/spray the clear water down the entire half (if you are spraying from a hose it's ok to do the whole window)
8. Using 6b towel and starting at the top, dry half of the window, flipping the towel if needed
9. Using same 6b after opening it to expose the inside dry half, dry other half of window
10. Using 6a, dry 1st half of the window again, only this time you're actually polishing it (kinda) to remove any streaks that 6b left
11. Using second 6a, polish other half of window

Voila! You should have no spots, no streaks, and when meal ol' Mr. Winter gets all over your car, the ice and snow will almost slip off as one large piece.

The only glass I don't RainX during winter is the mirror glass. Since the water beads instead of spreading out like a fog it's harder to heat up and remove with the defogger. Otherwise I use it on every window year-round.

PS: Don't buy the paste - it's junk. Get the spray bottle. NOT the cleaner, either, just the treatment.

 

Wax on glass can be cleaned with any solvent, it's glass, just don't get it on the paint.
Alcohol, lacquer thinner, enamel reducer, etc. will clean glass.
Side effect of the car wash, junk gets transferred onto you car from others who may not treat their car like you treat yours.

 

http://www.autogeek.net/mothers-wat...tm_medium=GoogleProductSearch&utm_campaign=CSE&gclid=COOVvsWZ77MCFU-d4AodYCwA1Q

I know nothing as to how this Mother's stuff works, just saw it on TV commercials.

 

When I had my 1999 Suburban, the owner's manual recommended Bon Ami cleanser on the windows if they had streaks, grime, or wax buildup.

I looked up the 1999 Owners Manual and it says this on page 6-54:

Cleaning the Outside of the Windshield,
Backglass and Wiper Blades
If the windshield is not clear after using the windshield
washer, or if the wiper blade chatters when running, wax,
sap or other material may be on the blade or windshield.
Clean the outside of the windshield with GM
Windshield Cleaner, Bon Ami
Powder (non-scratching
glass cleaning powder), GM Part No. 1050011. The
windshield is clean if beads do not form when you rinse
it with water.
Grime from the windshield will stick to the wiper blades
and affect their performance. Clean the blade by wiping
vigorously with a cloth soaked in full-strength windshield
washer solvent. Then rinse the blade with water.
Check the wiper blades and clean them as necessary;
replace blades that look worn.

I have used this trick ever since. Note how the owners manual says the windshield is clean when water doesn't bead on it. I find that going through car washes w/ Spray Wax treatments foul the outside surface of the windows. You have to get all that wax off first, then treat w/ RainX like DD says, or skip the RainX, and just keep the glass sparkly clean. Try the Bon Ami, it does work!