Hello Charles! I'm also starting The Master Cleanse in January and have located some grade C maple syrup which there is no longer any distinction between grade B and C. I'm awaiting anxiously my Stanley Burroughs book to arrive from my order at the Barnes & Noble book store. Not an easy book to find so I had to order it.
Anyway, I've also had some strange things come out during a liver cleanse. What I am most curious about is when I have a stone that looks like part of a bean sprout is coming out the side. It looks like a clear worm, but I still always wonder if it's something I ate.
Here's a crazy thought...mabye the shells that you describe are actually shells of nuts. I know the colon has pockets that holds onto seeds sometimes and doesn't pass. Maybe the Epsom Salts is moving something out of your colon that looks like a shell or a food you ate long ago? I have a relative with diverticulitis (sp?) who told me about this and that she can't eat seeds unless she chews them thouroughly.