I really like that he has only vowed to shave off his handlebar moustache. If he was really going to do it, he would have shaved it right away. That moustache isn't going anywhere, because the moustache is running the show.
I bet that any time he gets in front of the bathroom mirror and the vaguest notion of shaving the moustache off creeps into his mind, his face muscles involuntarily twitch, making the ends of the moustache bob up and down, and he hears a voice in his head - most likely an old-timey boxer's voice - saying "You don't want to do this, Charles. What would you do without me, Charles? A day without a moustache? Why, Charles, that would be a day where they all have to die, wouldn't it? Let's just go buy some more moustache wax, old chum. That way, Charles, we won't have to hear the screaming again."
You know, this could have been Spoony, if he'd continued on in his role as a moustache enthusiast.