What is the best window cleaner product?

There are different cleaning products for different applications. Typically, dish soap is a good cleaning agent when using window cleaning tools. The soap helps remove grease and grime from the windows and frames at the same time removing the friction away from between the glass and rubber squeegee tools. Water fed poles are a newer system that requires a filtration system to remove impurities from the water. The water is fed through a hose to a brush that scrubs and rinses the windows to remove dirt and other impurities from the glass. To remove hard water, using a cleaning agent like Winsol 550, Spot fade, or Sorbo powder can remove the calcium and other corrosion from the glass. Be careful, these agents have acidic properties and can damage windows and frames if not used properly. They can also be corrosive to metals. Some aftermarket cleaning compounds are available, but for typical window cleaning, dish soap is the preferred product used by professionals.