Billheiser
Headphoneus Supremus
.. Instead, I'm wondering if anyone has any ideas on how to fix the problem so that the owners can do it themselves. Anyone have experience sanding lacquer? Or maybe applying some kind of finish to the lacquer?
Yes, you can sand lacquer. As with any sanding, work your way down to finer grades and clean it (use a tack rag, for instance) to remove all dust before re-coating. Assuming this is lacquer (probably is), it's best to use lacquer on top. If it's a type of varnish, best to use that.