Ive been reading about freezing "kongs" with peanut butter in them, for strong chewing dogs. ( earlier threads regarding serious chewers) I've only used dry treats stuffed in kongs for my dogs. My question is this, when you use peanut butter, isnt it necessary to run the kong through the dishwasher or something when the dog is through? Is it difficult to clean the inside? I really want to try this, because I have two MAJOR CHEWERS and they both adore peanut butter. I just thought cleaning might be an issue...or maybe I'm just incredibly lazy?!... Advise please?