Abstract: An obliterating machine can be operated by means of a card, made of synthetic plastic material, that features longitudinal grooves and a toothing and that can be inserted in a receiving seat delimited by a pair of plates mounted within the machine and forming a profile complementar to the profile of the card. A couple of feeler pins, associated with respective micro-switches, are movable along directions perpendicular and parallel to the seat, and are designed to detect the presence of the card and of the first tooth of the toothing. A cogwheel is rotatably supported in adjacency of the seat so that it can engage the toothing, and a cutting blade is made to move in a direction transverse to the seat by an electromagnet to cut a strip from the head of the card while a rocker, that links the blade to the electromagnet, operates a further micro-switch to activate an electric circuit for controlling a vending machine.