The spitball shooter was one of the essential toys for a young boy at the turn of the century (Twentieth, that is). If he didn't have a spitball shooter, he probably had a slingshot. The spitball shooter was neater than the slingshot though. Other essential toys for the young boy were marbles and a penknife. That was during a time when boys were boys and girls were girls, and ne'er the twain met.
The spitball shooter was both an indoor and an outdoor toy. A young boy used the spitball shooter outside in contests with his friends, to see who could shoot a spitball the farthest. Inside he used it to shoot spitballs against the blackboard while the teacher had his or her back turned to the class.
A spitball shooter was a very simple toy to use; anyone, but a girl, could easily master it. The boy would tear a piece of paper off of something, such as a book page, stick it in his mouth and chew it a bit so that it got all wet with his saliva. (That was something a girl wouldn't be caught dead doing.) Then he would take it out of his mouth with his fingers and roll it up into a tight little ball. While it was still wet, he would pop the spitball into the end of the shooter and stick the end of the 'ramrod' portion of the shooter in behind it. He had to make sure that he did not stick the ramrod in too far to begin with. He'd aim the shooter at something (or someone) and give a quick push of the ramrod until it went the whole way in and the large portion of the handle came to a stop against the tube portion. The spitball would be sent flying through the air, hit the object, and stick on it. That was the glorious thing about a spitball ~ it stuck to whatever it hit and would dry there as evidence of the boy's prowess in shooting. (Of course if the target of the spitball was some girl's well-brushed hair, it might not stick there until dried.)
Boys today do not have spitball shooters to play with. All they have are video games and iPhone apps. ...Sad.