All that experience at the dogpark with poop bags is paying off. I nabbed his morning deposit and brought it in to thaw. Poking around was very productive...
several bits of blue plastic (the feeding scoop),
some bits of plastic of indetermined color (not sure what its from),
a piece of foil (the Yummie Chummie package perhaps?)
and one that threw me for a loop -
a green vinyl star about 1/2 " across! I have no idea what that came from .
Sherman got some more high fiber this morning. I'm still a bit worried about the big chunk coming through, but things look promising. At least the "traffic" is moving!

*thanks for the baggie tip Phred, the smell is pretty obnoxious.