I remove as much of the inner membrane as possible when I rinse them, then just let them air dry. When they're dry, I break them into pieces roughly the size of oyster shell, then feed. Mine like the shells, but don't throw out the oyster shell to get to the egg shells.
One thing I have noticed is that they definitely prefer natural oyster shell to the processed nuggets they sell as "oyster shell."
One thing I have noticed is that they definitely prefer natural oyster shell to the processed nuggets they sell as "oyster shell."