Excellent!! had stains so bad on a sink I had given up and thought I would have to replace--this stuff and a little elbow grease made it look sparkling new again!!! Yeah!
This stuff is great! I had used it several times in the past and was thrilled to find it on AMAZON finally. It works great! If you follow the simple directions: wet surface, rub small amount into stain - it works with very little effort. I've used it on my auto windshields and also on exterior windows of an older house.