Smash them with a rock. If they don't break, the rock isn't heavy enough. If the nut gets smooshed as well as the shell, the rock is too heavy. Iterate until yo

Smash them with a rock. If they don't break, the rock isn't heavy enough. If the nut gets smooshed as well as the shell, the rock is too heavy. Iterate until you find the perfect rock and then hold onto it like a sea otter.