Having been a clock repairman for nearly 40 years, I come across so many interesting situations. One of my most recent situations involved an antique clock purchased from a reseller in an antique mall.
The client was interested in this little Hamburg American Vienna Regulator style clock they saw in one of the booths at an antique mall. When the client asked the proprietor about the holes in the case, they were told it was "nothing of consequence" just an attempt to add "uniqueness" to the case by a former owner when they drilled holes in the wood for an aged appearance.
Once the client got the clock home they noticed "dust" falling on the floor from the case. The "dust" got so bad it bound up the clock movement. The "dust" the client was seeing was wood dust being expelled by wood worm