knocking on doors ,what if the area you are in already has a window cleaner could it be that there is pepole without, because he can!t manage or they just don!t want to use him, what if you are in an area and there is a window cleaner working do you still knock, or do you talk to him about what you intend to do ,because i would knot be happy if someone came cold calling in any of my streets, how do you approach this.