How do you clean your Kongs? Can they go in the dishwasher? I put a mix of food that has been soaked in boiled water and mashed, bananas, yogurt, and peanut butter in mine, and that seems like it could be fertile ground for a lot of germs. :yuck: I've just been rinsing them really well, but I'm worried about germs. My kongs spend most of their time in the freezer, so that has to help, but still I'd love to know how you wash yours.