A method of duplicating a key includes receiving a master key in a key duplicating machine. A voltage difference is created between two conducting lines in the integrated circuit to accelerate the bridging effect for a predetermined period of time. In an embodiment, the application of the electrical current does not substantially alter the viability of such cell andor preserves the viability of such cell. The apparatus also includes means for exposing the plasma chamber to a plasma, wherein the thickness is changed by the exposing, and means for determining the thickness as a function of time. Opposed rollers grip the tube and squeeze toothpaste from the tube as they are advanced by a roller advance screw along the tube.