To get the charge off of the electrophorus a large, round metal plate with a handle is used to perform charge by induction. Hold the handle and place the plate onto the electrophorus after it has been charged by rubbing. While holding the handle carefully the outermost pinky finger to the electrophorus to induce the charges onto the metal plate. Thecharge on the metal plate can then be transported and used to perform electrostatic experiments. Negative charged is a net excess of electrons.
Positive charge is a net excess of electon holes.
Robert C. Plumb, Triboelectricity, Journ. The electrophorus are stored in the electricity and magnetism cabinet.