Hi,
 
You can open it any number of ways, depends on whether you want to save the
sanddollar.  I have made shadow boxes in which I placed the shell, which I had
cut in half with a dremel, and had the doves flying out of the center.  I used
the round cutting blades that are red like an emery board.  It was messy, but
I did not loose any of the doves or shells.  The doves are right in the middle
of the shell.
 
Cathie