After 3 months of searching, baiting, and trapping, I think I found the
source of these little buggers. I was disconnecting the gas line from the
fireplace log set and noticed that a couple moths were in the fire box. I
figured a couple found their way around the screen. Anyway, I turned off the
gas for the pilot, and spread the lava gravel around to make it look a
little neater. 20 minutes later there are about a dozen moths in the
fireplace, behind the screen. I put a pest trap in there, and in less than
30 minutes, it was loaded with moths. Could these moths be in the lava
gravel? I thought they would only nest near a food source.

I removed the log set and scooped out all the lava gravel onto cookie
sheets, I am now "roasting" the lava gravel in the gas grill (500f for 20
minutes). I also sealed up all the little gaps in the firebox to seal in
any eggs/larva and vacuumed out all the dust and debris (and tossed the
vacuum bag into a garbage bag and tossed it out).

I was amazed to see that the moths were in the fireplace. I thought the
heat would have killed them. Anyway, I think I found the source (fingers
crossed). Has anyone heard of these moths nesting so far from a food
source? And being able to survive in a fireplace that gets a lot of usage?
They must be tough SOB'S!

Les