A system, comprising: a projectile launching apparatus configured to clean an inner surface of a tube by forcing a projectile through the tube along the inner surface, wherein the projectile launching apparatus comprises: a) a main body including an exterior surface, wherein the main body contains a breech chamber terminating in an exit port, wherein the breech chamber is provided with a loading port in a side thereof for radially loading the projectile into the breech chamber; b) a slide disposed over the exterior surface of the main body external to the breech chamber, wherein the slide is axially movable between a first position where the loading port is exposed for loading of the projectile into the breech chamber, and a second position where the loading port and the breech chamber are sealed; c) an air gun (18, 118) operatively connected to the main body in pneumatic communication with the breech chamber; and d) an exit nozzle connected to the exit port and being connectable to the tube to be cleaned, characterized in that the exit nozzle comprises a nozzle body having a threaded end connected to the exit port and a hose-barb end, whereby: (i) a hose-coupling is secured to the hose-barb end by a first hose clamp, whereby the projectile launching apparatus is securable to the tube having an entrance end for the tube to be cleaned by inserting the entrance end into the hose-coupling and tightening a second hose clamp, or (ii) a nipple is secured to the hose-barb end by a first hose clamp, whereby the nipple has a terminal end smaller in diameter than an entrance end of the tube such that the nipple is sealingly insertable into the entrance end before firing of the projectile launcher. a) a main body including an exterior surface, wherein the main body contains a breech chamber terminating in an exit port, wherein the breech chamber is provided with a loading port in a side thereof for radially loading the projectile into the breech chamber; b) a slide disposed over the exterior surface of the main body external to the breech chamber, wherein the slide is axially movable between a first position where the loading port is exposed for loading of the projectile into the breech chamber, and a second position where the loading port and the breech chamber are sealed; c) an air gun (18, 118) operatively connected to the main body in pneumatic communication with the breech chamber; and d) an exit nozzle connected to the exit port and being connectable to the tube to be cleaned, characterized in that the exit nozzle comprises a nozzle body having a threaded end connected to the exit port and a hose-barb end, whereby: (i) a hose-coupling is secured to the hose-barb end by a first hose clamp, whereby the projectile launching apparatus is securable to the tube having an entrance end for the tube to be cleaned by inserting the entrance end into the hose-coupling and tightening a second hose clamp, or (ii) a nipple is secured to the hose-barb end by a first hose clamp, whereby the nipple has a terminal end smaller in diameter than an entrance end of the tube such that the nipple is sealingly insertable into the entrance end before firing of the projectile launcher. (i) a hose-coupling is secured to the hose-barb end by a first hose clamp, whereby the projectile launching apparatus is securable to the tube having an entrance end for the tube to be cleaned by inserting the entrance end into the hose-coupling and tightening a second hose clamp, or (ii) a nipple is secured to the hose-barb end by a first hose clamp, whereby the nipple has a terminal end smaller in diameter than an entrance end of the tube such that the nipple is sealingly insertable into the entrance end before firing of the projectile launcher.