Abstract: A method for forming successive spaced crimps in a tow of fibrous material by passing the tow along a path defined by an apparatus comprising a plurality of crimping wheels disposed around the path, each wheel including teeth having crimping surfaces and adjacent sealing surfaces which slide over one another during crimping to prevent material from being squeezed between the teeth thereby forming crimped sections with elongate edges which are substantially free of flashing connecting non-crimped sections. A second crimping step may be incorporated to form longitudinal grooves in alternate non-crimped sections. The rod-like member produced by these techniques may be overwrapped to provide pockets surrounding the crimped sections which may be filled with a smoke-modifying material, for example, activated charcoal particles. Discrete elements cut from the rod-like member may be used in cigarettes and the like such as in the production of filtered cigarettes.