Hard water mineral deposits on exterior windows. Clean with a soft abrasive cleaner. Follow safety precautions and avoid extensive contact of solution with surrounding surface. Adjust sprinkling systems so that they do not spray hard water onto windows when watering the lawn. Films, iridescent look, hard water deposits.
Vinegar removes hard water deposits from glassware.
Soak glass 15 minutes in undiluted white vinegar. Rinse and dry. Use commercial products available for glassware to remove hard water deposits. Use a rinse agent in the dishwasher. Hard water and not enough dishwasher detergent may leave hard water minerals on surfaces of glassware and interiors.