I just read the wikipedia page for window cleaners,He is talking about sqeegy into the corners when they are really grotty or spider webed and then washing them, Some Guuurmans "wet up" the windows then cloth the edges, then sqeegy off. (If you see what I mean) No detailing needed then.
http://en.wikipedia.org/wiki/Window_cleaner
made me smile in a few places, think it must have been written by a trad guy
:)
What is this corner wipe method, I've cleaned windows for years and never heard that one!