A building’s metal surfaces, including window frames and aluminum composite panels, can develop the same unsightly stains that glass and stone develop. Detergent and other environmental grime collects on the frames, developing a high concentration of contamination. Often, window frames have many years of buildup that needs to be removed, since frames are usually not cleaned on a regular basis. Instead the opposite occurs since dirty water is deposited on the frames during the window cleaning process and never removed.