I must confess I tend to keep my weathering on civil stuff reasonably restrained. However, I found this album on Airliners.net and it has certainly got me thinking...
http://www.airliners.net/search/photo.search?album=31542&thumbnails=noinfo&page_limit=120&photos_in_album=65&album_name=Dirty+Airplanes&album_creator=LesageCyprien&disp_order=desc
Some great ideas for 'dirtying up' your next civil build
Kev1n.... control yourself
Tom