So a while ago we stayed at Mary’s folks’ apartment in Saratoga Springs.
We parked in the Visitors section of the lot in front of the rental office and, the next morning, the windshield had a bunch of whitish water-droplet-sized spatters. The previous day had been a bit rainy and we drove home over some wet roads, so I thought nothing of it; that’s what windshield washer juice is for.
But the spots didn’t quite wash off: most of the white center went away, leaving an oval outline with a line across the middle. The spots now looked like a Greek capital Theta, as though each droplet had landed on the window, slumped to the bottom of the wet area, then evaporated.
I discovered that diligent rubbing with windshield washer juice and a soft rag didn’t remove the Thetas. They looked, alarmingly, as though they’d etched their way into the glass: thin lines emerged from the rounded outline, with a sort of crinkly surface finish.
Running up the hazmat scale, I applied homebrew glass cleaner to no avail. Then I deployed denatured alcohol. Ditto.
Finally, I had a bright idea: glugged some vinegar on a rag and wiped those suckers right off, leaving the windshield sparkly clean!
As nearly as I can tell, the apartment watered their fancy new sod overnight with genuine Saratoga municipal water through below-ground sprinklers. Yup, water straight from the same aquifers supplying the local mineral baths. Maybe cleaned up a bit, but certainly not softened.
Hard water spots on the windshield, indeed!
And, yup, soap doesn’t lather worth a darn in their shower…