Pile of unshelled pistachios
How To Open Pistachios When The Shell Is Totally Closed
While some pistachios have a wide-open split that makes them easy to shell, some have a narrow crack that requires extra effort, and some are sealed completely shut.
Although you can buy a tool specifically designed for the job, shelling pistachios requires nothing but a heavy tool capable of cracking those pesky shells without getting damaged.
Wrap your pistachios in a towel, and gently pound them with something like a cast iron pan, rolling pin, or meat tenderizer. Your aim is to break the exterior, not the nut inside.
After you've cracked the shells, carefully separate any broken pieces from the nuts to ensure safe snacking. Do not use your teeth for the job, or you might end up chipping them.