A cleaning bullet for use in a pipe or track includes a compressible body. In one embodiment, a sheet draped over the body is engageable with interior walls of the pipe or track to clean small contaminants, hi another embodiment, the body is formed from an absorbent material that absorbs a fluid, such as a cleaning solution, that can clean and/or disinfect the interior walls of the pipe or track. In yet another embodiment, an alignment key extends radially from a body axis for guiding the cleaning bullet in an air conveyor track.