This water spot remover has a strong acidic mixture that softens the hard minerals that have been left behind by hard water especially by lawn sprinklers.
Spread a small amount on cool glass or paint of the car. Rub in with a towel and rinse off. For extreme conditions repeat process using a Scrub Sponge. Although 3D Eraser GeL is a mild based acidic product, do not leave it on any surface for more than 1 MINUTE. Longer periods might etch glass. Best to re-wash area using a PH neutral car wash to neutralize Eraser.