An idea for a demonstration to be done by instructor to set up motivation for aseptic technique, pointing out that we are normally surrounded by bacteria, and the role of phage in our environment (in regulating bacterial numbers).

A section of a dollar bill was lightly pressed against a plate's LB-agarose for 90 s.

The dollar is then washed and dried and the plate examined after a day or more.

The plate edge should be wrapped in parafilm, not opened (do not expose yourself or others to amplified numbers of unknown bacteria), and the autoclaved when finished.