Washing glass windows with hard water commonly causes them to acquire cloudy stains over time. Since hard water is prevalent in household water systems, homeowners tend to clean household surfaces with it. Calcium and magnesium content in the water actually produces the unsightly white streaks and spots on window glass. Fortunately, hard water stains are harmless and only temporarily mar glass's appearance. Promptly clean hard water stains from window glass because mineral deposits slowly become more stuck-on over time.
Cut or tear clean paper towels into strips large enough to fully cover the hard water deposits on the window.
Dip the clean paper towels strips in distilled vinegar. Fully soak the paper towel strips.
Place the soaking paper towel strips on the window glass, directly over the mineral stains. Thoroughly cover the white stains with the strips.
Keep the soaking strips on the window glass for an hour. Distilled vinegar is known to dissolve hard water stains on glass. If the strips dry out within the hour, resoak them in vinegar.
Remove the strips from the window glass.
Buff the glass with fresh paper towels to eliminate any remaining vinegar residue from the window.
Substitute pure lemon juice for distilled vinegar. Lemon juice and vinegar are weak acids that dissolve mineral deposits.