Once your puppet is ready, say the pray - you know the one, they close every broadcast with it - and leave it exposed to the sky overnight. It doesn't matter where specifically, but light from the blue star (again, you know which one) has to hit it. And there you have it, an instant Muppet. They don't last too long if they're just socks, or, if you're feeling particularly nasty, paper-bags. The higher the quality, the longer they live. Of course, once they reproduce, they have a normal natural lifespan, but that can be readily solved by pre-neutering them. Just don't let them escape, or they'll make the problem worse.
It all started in the mid-70s, as the Feltoids started being created. At first, they were just on children's shows, as is natural. Then, they began to appear elsewhere. News anchors, police shows, the works. And then they demanded equal rights. They changed the history books, trying to obscure the fact that they were the inferior species, if such a term could be applied to things made of cloth and felt and wood. And they succeeded. They fooled our children, and their children, who thought it was only natural to have these things as real policemen, executives, even government agents, taking away jobs from the better qualified humans, and slowly taking over society from within.
It's time to put an end to this, to the reign of the children's toy. It's time to rise up, and hand them their own stuffing, to put them back in their place, where they belong.