Never mind...

I have wrist weights that are for working out that I thought were filled with sand. I use them to prop things up in the laser as well as hold things down. I just moved one to look around the laser bed for more of the mystery discs and viola, more of them "magically" appeared. The stupid things are filled with metal, not sand and there was a tiny hole in one that was leaking them out. I am not sure why they are magnetized, but at least I know where they are coming from now.

Gary