Bruce, I've had two termite infested frames. One from a leaky skylight, and one from a leaky roof. In both instances I went on site to retrieve the art.
The termites are subterranean variety, and leave the ground at night to forage along wet pathways, and return during the daylight hours.
As with your customer's there was but a single hole in the dust cover. I would wager that the roof leaked, attracting the termites and they ate the exterior and interior walls from within.
Mary Beth, you can make a little coin with these leftovers, but they cost you the space they take up as opposed to product that can make you more coin. I am very sympathetic with folks that save scrap and freebies to make few bucks, but the time and maintenance really isn't worth it. I have bought (probably too much) what I call "Tomato Stake Moulding" AKA so cheap, you could use it in gardening. It pays for itself pretty quickly, but then there's the storage of the rest. I'm still guilty of that, but at a different level. The problem is space is finite, and no matter how good the deal, if you can't manage it, it isn't a good deal.