Remember that if you're going to do climbs at the base of El Cap, it is critical that everyone wears a helmet at all times. All kinds of stuff gets dropped off the walls all the time. While putting on his harness at the base of the Nose, my partner was hit with a short -thick Lost Arrow piton that was dropped by the party on The Shield, 15 pitches above. It gave a pretty nasty bruise on his arm. I've also found biners, food cans, other misc gear, a camera, and a boom box at the base of El Cap.