My Touareg got hit with some sprinklers while visiting family our of state. They would not wash off, nor come off with a clay bar. I tried some Optimum Hyperpolish by hand, which worked mostly, but I did not want to polish the entire hood (worst part). I've been really into the Carpro line so I ordered their water spot remover, Spotless. The spots had baked on for about 10 days, many in 90+degree heat and direct sun on the black paint. Spotless removed them no problem, 100%. Thankfully they had not etched into the paint. Very pleased with the performance of another Carpro product. Side note, the car has Carpros silica based sealant Hydro2 AND Reload on the hood, applied a couple months ago. Perhaps this prevented the water spots from really being able to take set, I can't say for sure. What I can say is Spotless worked much better than clay and much easier than polish.