By eHow Sports & Fitness Editor
Familiarize yourself with how cams work before you leave the ground: Retractable cams expand in the crack to hold the piece in place.
Put your fingers on the trigger bar of the cam, and put the thumb of the same hand on the end of the stem.
Pull on the trigger bar at the same time you push on the stem. This causes the cam to retract.
Remove the piece from the rock if it's easy. (It will be easy if the cam was placed in a parallel-sided crack.)
eHow Sports & Fitness Editor