a method of retracting a filmstrip wound on a filmstrip reel . the filmstrip has a rear end which is attached to a spool of a film cartridge . the filmstrip reel comprising a pair of side walls , each side wall having a spiral track for retaining an edge of the filmstrip . the filmstrip is rewound into the film cartridge by applying a removing force on the rear end of the filmstrip in a direction for rewinding the filmstrip into the films cartridge . at the same time , one of the side walls is oscillated with respect to the other side wall about its central axis .