iv been window cleaning for years now but never targeted the commercial sector i now want to target them but not sure what is the best way. if im driving along a road and see a big building i think id love to be cleaning that but do i just walk up and ask whoever answers the door, do i ring , do i write them a letter and who do i even ask to speak to dont want to look like a fool i want them to see me as profssional as my domestic customers do is there anyone in the know would give me some advise