Product Short Description: Remove stubborn hard water spots and stains from any exterior glass surface. Powerfull mineral-disolving agents scrub away sun-baked sediments, salt spray, tree sap, road grime, bugs and paint overspray. Product Description: Spot Remover is designed to remove stubborn hard water spots and stains from any exterior glass surface. Powerfull mineral-disolving agents scrub away sun-baked sediments, salt spray, tree sap, road grime, bugs and paint overspray. Use RXSOL Water Spot Remover on exterior glass windshields, windows and mirrors. Hard water spots, all that’s left behind is lime-scale and other mineral deposits, like calcium and sodium. Unfortunately, the stuff that’s left behind is super-concentrated, so it’s hard to see through and even harder to remove. Water spots are a mixture of water and soap, acid rain, or some other type of contaminant. When the water dries, all that’s left on your windshield is the chemical.