Bic make a couple of different cases that will keep a mini-bic from discharging it's fuel, they've been referenced here before. The Bic website is not cooperating or I would post a link or pic, but check your local 7-11 or Wal-mart.

While we're on the topic, does anyone have experience with butane inserts for Zippo lighters? Like this:

http://www.elighters.com/zplus.html