Things You'll Need
Instructions
Disassemble the pen or pencil. You want to use only the plastic tube casing of the pen or pencil, so unscrew or pull loose the point of the pen and the end of the pen.
Throw away the interior pieces of the pen or pencil such as the graphite or ink cartridges. You want an empty tube so that you can propel the spit balls.
Cut the pen or pencil casing, if necessary. If the pen or pencil, once disassembled, does not make an open-ended tube, use a handsaw to cut the closed end off the plastic tube.
Test the spit ball gun to make sure it works. Tear off a small section of paper and wad it into a ball in your mouth or with your hands. If you make the ball with your hands, dip it in water to produce a moist ball.
Place the spit ball into one end of the plastic tube. The spit ball should sit tightly inside the tube or stop up one end of the tube.
Blow hard and rapidly into the open end of the spit ball gun and see if the spit ball propels out of the gun. If it does not, you may have made too large of a spit ball or gotten the spit ball lodged in the gun, or you may need to make a new gun.