oh nuts!

I love the garlic press idea. I bought one years ago thinking it would make life easier and quickly gave up on that idea. I'll have to resurrect the thing from the muddle at the back of the drawer. I'll also try the roasting idea!

The shell splits when the nut is ripe, i.e. unopened nuts are immature. However, the only danger would be from breaking a tooth trying to bite one open. You can crack them with a nut cracker or a garlic press (and you thought a garlic press was a one-task tool).

I thought I once heard unopened pistachios are like unopened clams - if they are not open then toss them.

I just use a nutcracker... works pretty well! :)

You might try to roast the closed nuts for a few minutes in a hot oven to see if they crack. Even if they crack just a little bit, they'll be easier to get into. If you can get a small access point, you can pry the two halves of the shell open with another half of an already-eaten nut.

I hate to say it, but I usually toss those out. I have come so close to cutting myself or smashing my fingers that I finally decided it was better for my body to just pitch those few nuts. I hope someone will post a good suggestion on this.