I am a new boat owner. I was told to use vinegar and water to remove water spots on the boat. This worked well for the body, but the glass has a few that are not coming off. I tryed to see if I could rub or scracth them off with my finger and that did not work at all. I even used vinegar from the bottle, "un-cut" with additional water. I know there is a trick out there. Please send help!