Tap water is passed through a series of filters and resins, making use of a deionisation process, this means the water 100% contains no dirt or minerals that will dry leaving a deposit that appears as a stain.
The pure deionised water is then applied to the glass and agitated by a particular brushing technique, that causes non stained pure clean windows.
Tap water is passed through a series of filters and resins, making use of natural processes like reverse osmosis and deionisation, then applied to the glass and agitated by brushing.
Due to the unnatural absence of dirt particles in the water, the pure water has the capacity to literally attract dirt from the glass into the water and then be washed away in a cohesive sheet of water. Because the cleaning process has used pure water, the windows can then be left to dry naturally, with a perfect crystal clear finish.