A cleaning system for cleaning a pneumatic conveyance system used to transport particulate material. The pneumatic conveyance system includes a material-introduction device for introducing particulate material into a convey line, and a motive air source for generating an air flow to propel the particulate material through the convey line. The cleaning system comprises a projectile comprising a cleaning surface for cleaning an interior of the convey line as the projectile travels through the convey line, a launcher for injecting the projectile into the convey line, with the launcher being coupled with the convey line at a position upstream from the material-introduction device, and a catcher vessel for receiving the projectile upon said projectile exiting the convey line.