The magician displays his "detective cards," two blank-face cards wrapped with a rubber band. The spectator may take the band off and completely examine the cards as much as they like. The spectator then freely selects any card from a shuffled (possibly borrowed) pack and can even sign the card. The card is returned to the pack and lost. The spectator puts the band back around the detective cards and hands it back to the magician. The magician simply snaps his fingers and spreads the detective cards apart, showing there's now a face down card trapped between them, which turns out to be the spectator's selected card! It's just that clean!