Personally, I'd rather them be a little germy than put them through the dishwasher or use chlorox on them. Those chemicals get absorbed into the rubber most likely and never completely get rinsed off. I don't want my dogs gnawing on something that might have residue of those chemicals in it. When I do clean them, which isn't that often, I just soak them in the sink in hot water...maybe add a little regular soap, shake them up, use a bottle brush and rinse well. But of course, I don't give them peanut butter or anything in their Kongs every day....hardly ever, as a matter of fact. LOL. Remember, dogs eat disgusting things, like poo and road kill. They can handle a little crusty old peanut butter.