Bill Tube by Tango

Effect

The magician borrows a bill, ask to sign it, and places it under a handkerchief. He then gives the handkerchief, with the bill inside, to a spectator and shows a closed tube of bronze. Gives the tube to the other spectator with the key for the padlock. He then throws one of tops of handkerchief and the bill doesn't fall down to floor, it's disappeared. Immediately, request to spectator (that has the tube) open it and inside of tube will be the bill with the sign. Finally, give all items to examine.