To open a pecan in its shell, use a nutcracker or pliers and gentle crack the shell. You don’t want to crush too hard that it smashes the pecan meat into pieces as well. Remove the outer shell from the pecan meat. Then gently break the pecan into two halves and remove the shell material holding the two halves together and in the cracks. I believe there is a tool you can use to pick the shell out without breaking the two halves, but I preferred the two halves anyway.