Modern day window cleaners do all their work from the safety of the ground, with vehicle mounted reach and wash systems.
Using reverse osmosis and deionisation technology tap water is purified removing all traces of dissolved minerals and impurities. This water is transported in large vehicle mounted tanks and then pumped up telescopic poles with brush heads at the end. Dirt is scrubbed from your frames, glass and sills, then the window is rinsed and left to dry naturally. As the water is pure it dries without leaving any marks. No more dirty water or cloths that have been used on other houses.