A cassette for packing waste material into an elongated tube of flexible material is provided. The cassette includes a ring-shaped receptacle defining a central opening and a storage area for receiving the elongated tube of flexible material. The cassette also includes a cover at a top portion of the storage area and a plurality of projecting elements extending from a periphery of the cassette and being configured to support the cassette in a waste storage container. Also provided is a cassette which includes a lip having a variable projection width. A waste storage container is also provided including a cassette holder having a hollow area for removably receiving a cassette, the cassette being configured to matingly fit into the hollow area.