The answer to 'window stained' is that there are several common causes for stained windows, including mineral deposits, hard water buildup, environmental pollution, and improper cleaning techniques. Symptoms may include visible streaks, spots, or a hazy appearance on the glass.
In many cases, window stains can be removed through DIY cleaning methods. However, for more stubborn or extensive staining, it's best to call in a professional window cleaning service. They have the right tools, products, and expertise to safely and effectively restore your windows to a clear, streak-free condition.