Harvest shagbark hickory nuts that have fallen from the tree within the last few days.
Bring the nuts home and remove the green husk. Some may be stuck in the husk, put those on a tray with a fan blowing on them in a garage overnight and they should remove.
Submerge the fresh nuts in water and discard any that float.
Set the nuts on trays out to dry with a fan on them for 2 weeks, then store in the freezer or in a cool dark place. If the nuts aren't frozen they will last 3-4 months.