best way to clean air vents in cab?

[chevytruckclassics]

well the 67' k10 (originally a c10) is done and back on the road after 17 years! and after driving it a LOT of mouse nest and leaves came out of the side air vents in the cab by the pedals. (if you guys dont know what im talking about ask for pics and ill post some) i was wondering what the best way to clean them was? my vaccum hose wont fit in it well. i just figured to just keep driving it until all the crap comes out!