Review on 10 Ounce Diamond Shine Professional Window and Glass Hard Water Spot Polish - Ideal for Car Windows and Shower Doors - Effective Water Cleaner by Bonnie Nieves

Use this product on the roof of an eight year old glass solarium. In Miami, Florida, it rains a lot and deposits build up on the glass, causing it to fog up. Based on a roofer's recommendation I used the product in combination with 1000 grit sandpaper and water and LOTS OF SOFT circular rubbing (elbow grease). It took about an hour to clean the 2 x 3 foot glass pane. The combination of sandpaper with permanent water and product will remove most or all of the stains. Others may get less results just using the product alone. Always start by testing on a small area. Using sandpaper left very thin round lines on the glass. Try to put the LIGHTEST pressure on the glass. The lines are not visible inside the tanning bed and compared to what was bad it's like night and day. I'll try it on an old windshield. Give your elbow a rest.