As war flicks go, this is a fun one. Fantastic cast.

Man.

Just before the phony ambulance arrives to capture him, they start collecting what looks like pencils and put them in a knapsack. I never figured out what that was about.

I've worried about the same thing for years

They were used throughout that scene (in the book) for distractions.

That's taken from the IMDB board where the same question was asked. I read the book years ago, but don't recall that part of it. Another theory claimed that they were the firing pins of the enemy's rifles, but that doesn't seem probable.