No, I haven't, but I've seen several questions related to insects in old bears and the usual answer to get rid of them is put the bear in a freezer for several days. And the suggestions came from knowledgeable, long-time bear artists, so I assume it is at least something to try.
Works a treat. A few years back I happened to come across an old bear very cheaply with moth problems. Popped her in a bag and in the freezer she went. Most amusing for the rest of the family as the talk of the body in the freezer of a frozen teddy bear circulated amongst family and friends. It done the job nicely, and stopped the infestation after a few days. Just to make sure she went back to the freezer a couple of weeks later. The quicker you can catch insects the better otherwise its ragged paw pads, sawdust and a summer bear (without a fur coat).