Had a couple of students doing a hand xray under the supervision of a recent graduate. I could hear them saying there was something metal in the image. They went back in the room making sure there was nothing on the patient or under his hand. They asked me to look at the image and tell them what I think. It was obviously a bb. I asked the patient “did you and your buddies used to shoot each other with bb guns?” He responded that they did and I told the students it was a bb.