I have my own set of rules about what I pick up and bring home, foundlings must be :
found in circumstances where it is not possible to trace the previous owner ;
clean ;
non-porous (so I can clean them properly) ;
beautiful/interesting/useful.

The little charm in the bottom right-hand corner deserves a close-up :

Not easy to photograph, being so small and intricate, but it is a tiny bird-cage, with an opening door, and a little bird on a swinging perch.
It's just ordinary metal, no marks, about 2.5 inches tall and someone has clearly taken a lot of time to make it.
Does anyone else collect "foundlings"? Do you have your own set of unwritten rules?