When a walnut turkey does not pass quality control due to a cracked nut, there's still a chance that the other half can become a walnut shell ornament (or if not, then maybe a snack!) It's fun finding things that are small enough to fit inside. They make perfect nests for miniature mushroom birds. What is the best way to split a walnut exactly in two? It's best done by mother nature. If it's already starting to separate, pry gently with a paring knife. Or even better, visit your local grocery store that sells walnuts in an open bushel and you can find perfectly separated walnut shells among them. I'm one of the nuts that shops only for the shells.