Ajax for Water Spots

My brother parks his car on the street and every night the sprinklers go on. When he wakes up in the morning, he has water spots on the right side of his car. He tried washing his car but the spots would not come off. He also tried Windex, white vinegar, brake cleaner, anything you could think of!

Then my mom said, "Hey, try this Ajax!" With a little bit of water, the spots came right off! So the trick is AJAX!

Hope this helps.