I'm doing some paint correction on the coupe. There's these stubborn stains on the hood and roof which look to be water marks (maybe etched in?) that I can't remove. I've tried using a clay bar, vinegar with a towel, nothing. Hit it with Meguiar's Ultimate Compound using a PC-7424XP, used an orange pad, nothing. Stepped up to a yellow pad still nothing. How can I get rid of these marks?
Here's a couple of pics showing the marks. Thanks!