I put each one in a tiny (2" x 3.75") reclosable plastic bag, and include a slip of paper with the details written on it. These bags are sold for use by people

I put each one in a tiny (2" x 3.75") reclosable plastic bag, and include a slip of paper with the details written on it. These bags are sold for use by people who do beading. I keep the bagged flash drives in a small cardboard box.