Hmm, yes, I've always wondered how they are cleaned. I found this link which shows a very illogical way of doing it.
http://www.darkroastedblend.com/2007/05/how-to-wash-airplanes_06.html
doesnt the rain wsh them?
That's true . I always use the same idea/excuse for not washing my car though, hoping that the rain would wash it!!!
Im sure Air France use the rain washing technique, they never seem to use any soap