Opening pistachios is typically very easy. Most of the nuts come with a small opening in their side that you can easily put your fingers between to pull the shell off of the nut. Sometimes though, the pistachio shell hasn’t fully cracked and despite your best efforts, your fingers just aren’t able to get enough of a grip to pull the nut apart.
To combat this problem, you can use the husk of a previous nut to push into the available opening to pry the shell apart. With the shell pushed into the opening, turn it like a key so that the upward pressure of the shell’s edges pushes the other shell off of the new nut.
Alternatively, if the shell is too stubborn to be pulled apart by a previous pistachio shell, you can use a pair of pliers to crush the nut’s shell to gain access to the deliciousness inside. But be careful when you try and use pliers to crack the nut apart, as too much pressure with the pliers’ grip can cause the entire nut to shatter all over and you’ll be left with nothing more than nut crumble.
Finally, if your entire batch of pistachios aren’t ripe and haven’t yet developed a crack to pull them apart, you can use a penny as an alternative to an old shell husk to twist the shells off to gain access to the nut.