Tips on how to clean a stuffed animal with a voice box in it?

My 2 year old son LOVES his Mickey Mouse and Poe stuffed animals and takes them everywhere. As a result, they look quite worse for the wear and he is at the lovely stage of taking his diaper off at night and peeing in the bed. Both of the stuffed animals have voice boxes inside that while there is a place to open the animal in the back, there is no where to unplug the box as far as I can see. I'm looking for any tips on how to give these toys a GOOD cleaning so they smell and look as fresh as they can.