Most unusual thing you collected in the military?

Remember the scene from 'Saving Private Ryan' where a Soldier collects soil in small cans? I have done that since joining the Army. I also got permission to snag a few colored rocks from 'the box' at National Training Center, Ft. Irwin, CA. What is something 'unusual' you collected or still collect while in the military? And no, we aren't talking about Article 15s.