With the help of my little tree identification book, I misidentified our local hickories as Pignuts - until I ate one. I read that pignuts are usually pretty awful, so I tried one of ours to see if it was a less awful variety, but they were delicious. I did some more research and found that my ID book was not very thorough, and that what we have here are black hickories.
The sap from hickories can be processed the same as maple, but the sap is less sweet. I was considering doing this when I thought we had pignuts, but tasty varieties of hickory nuts sell for $5 a pound (unshelled!,) so there is no way I'm going to steal sap from these valuable nut trees.
First, hull all of the nuts. Black hickories hull easily, and do not stain hands. If the hulls aren't pretty easy to get off, set them aside for a few days. Just be sure not to put them anywhere that animals can get to them. If you peel the nuts from the bottom up, it's pretty easy to remove the stringy fibers that cover the nut at the same time. I noticed some worms in the hulls, but not in the nut shells. I think the worms wait until germination when the shell cracks and then sneak into the nut. Do not throw the hulls back under the tree, as this may encourage the insect cycle.
Next, put the nuts in a sink or bucket and add water to allow several inches of water above the nuts. The nuts that are not good will float to the top. Take out the bad nuts, and stir up the rest of the nuts to allow nuts closer to the bottom to rise.
Then, remove the nuts and place on a towel to dry a bit. After a few hours, move them to trays and allow them to dry for several days. Store somewhere that will allow air to more between the nuts. I've read that mesh bags are good for long-term storage, and that nuts stored properly in the shell will stay good for months and months. In fact, the longer they dry, the more compact the nutmeat will become, making them easier to remove from the shell. (UPDATE: It has been 8 months and nuts stored indoors have not had nutmeats become any more compact, but are still delicious.)
The cheapest way to shell hickories is to put them between two lengths of cloth on a concrete surface and smash them with a hammer or brick. Open the cloth and take out the bits. I've read that if you put the smashed nuts in water that the nutmeats will fall and the shells will rise, but I've not had enough luck getting the shells to remove cleanly from the nutmeat to bother with this advice yet. (UPDATE: I've tried this and it does not seem to work.) Hard-shell nutcrackers can also be purchased from companies like Lehman's with a cost of about $40.
Bury the floated nuts from processing anywhere you would like hickories to grow - some nuts float because they have already started sprouting. Try to break the life cycle of worms by cleaning up all the old nuts and hulls from under trees at the end of the season.
About our black hickory trees: Our Oklahoma hickories grow in the margins of wooded areas as well as along fences. We have seen them on the west, east, and south sides of woods. They don't seem to be tall enough to compete in the woodland canopy. I started collecting nuts around the end of September, 2013. One tree was already done dropping its nuts - it is in a fairly isolated, sunny area. Perhaps the additional light caused it to ripen earlier. The summer here was not as warm as usual (few days above 100 degrees, and none approaching 110,) and September was warmer than others have been, so I cannot say that the ripening time will be the same in other years. I also do not know if the excellent rains this year have caused an increased yield. One tree in an isolated, full sun area produced nuts earlier, as noted, and another isolated tree only produced about three nuts. The other two trees have yielded 30-40 pounds, but still have many nuts on the tree.
Update: I did a survey of trees on our west fence in late fall, around November when the leaves changed color, and found that we have easily a hundred hickory trees, with more on the south fence. I have decided that we have enough trees to tap a dozen or so. I got spiles for Christmas, but I still need a book on how to do it and some buckets, so maybe next spring. That will give me time to find the biggest trees and mark them somehow.