Slimy nunchuk control stick?

Infendo

Sorry if this grosses you out. I think I’m more disgusted than any of you, though. I’ve noticed that if I don’t use my Nunchuk for a few weeks, the control stick builds up some seriously nasty slime. I never eat when I play video games and I don’t smoke. What’s more, I’m kind of a germaphobe, so I wash my hands A LOT. That includes before and after I touch video game controllers. What could possibly be the cause of this?

Does anyone else have this problem?