I collected some hickory nuts from trees in the neighborhood and put them in a plastic bag in the garage. Left the garage open in the morning and came back in the afternoon to cracked hickory husks all over the garage floor. I'm going to kill some squirrels...

BTW, hickory nuts are delicious - in the Walnut & Pecan family but much harder to crack & extract whole nut. I'd recommend trying them if you haven't already.