I gave Eraser a try today on a two week old group of water spots (while driving through a tunnel, some water dripped on the roof).
I didn't notice until a week later, so it was too late to wipe off. Anyway....Eraser didn't touch it. Also, car is OptiCoated, so hopefully the paint is OK. Chemical Guys have a water spot remover : Chemical Guys Water Spot Remover - 16 oz | Detailed Image
