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A Ball-Point Pen is THRUST thru the center of a borrowed signed dollar bill.
Show that it's clearly Piercing the bill. The Pen is removed and bill is returned!
Only 1 Pen is used.
You borrow a bill from a spectator.
You hand them a pen to make a mark on the bill.
You take the signed bill and stab a pen right through the bill.
You then move the pen and hole to a different spot on the bill.
You pull the pen out of the hole, but where is the hole?
You give the bill back to the spectator.

Very easy to do.