A Shabbat guest told me that he had heard that there is a custom to put a cracked egg shell on a dead person's eyes and a piece of pottery in the dead person's mouth prior to burial.
I'm completely unfamiliar with this custom if, in fact, it is one. My guest didn't recall where he had heard this, and, of course, I couldn't confirm this either way.
Is there such a custom, and, if so, what is its origin?