I did a leaflet for customers explaining the new system, and how it would work etc.
Went down very well, they need to understand why the windows will still be wet after you leave. Also, when writing it, make sure you emphasize the safety aspect as thats something nobody can disagree with.
I dont share the text of this leaflet anymore I'm afraid, but I can tell you, as justin says, pictures make all the difference.
-Philip