I am a new window and janitorial business in a rural county. Northern California. I want to learn how to market and contract window cleaning for large complex's(Apartments, Hotels, County/City). Any advice always helps. I have big expectations for this coming spring (residential), but in the county next to my own there is a robust thriving metropolous. I would like to travel and tap their financially well off communities. Does the "KNOCK KNOCK" really work? Just one more I promise. I have noticed that window cleaning pro's are using pressure washers for exterior surface cleaning. Is this the best extra service to offer and how would you recommend i properly clean window screens? Ok, I lied, is there a tool for screen removal?