Abstract: A policing key for regulating the type of toner in a copying machine or other toner consuming machine includes a base mounted to the toner-consuming machine and a boss projecting from the base to a position between a port on the machine and a toner bottle cap prior to engagement. The boss protrudes above the periphery of the toner port that contacts an annular brim of the toner bottle cap, precluding the toner bottle from engaging the toner port while the key is in place. Only the annular brim of an approved toner bottle cap, which includes a notch associated with the boss for bypassing the policing key, can be used on in connection with the toner consuming machine. By varying the size and shape of the policing key, the restrictions on the type of toner used in a particular machine can be effectively controlled. In a preferred embodiment, a hardening gel is placed over the base of the policing key such that removal of the base will disturb the hardened gel and indicate a tampering of the key.