1. Gravel driveway ~ pour them out on the drive way and run the car on them on and off over a couple of weeks. In earlier times they drove the tractor over them, and even earlier the wagon, or just had the horses stomp on them.
2. Large hunk of iron. A piece cut from an old railroad rail is good. I have one outside if you'd like to see how it's done.
3. A large 2.5 pound hammer. Any lighter than that it might bounce off.
Let those husks get off by themselves. Then dry 'em out. Lay a walnut on the rail. Pick up the hammer and let it drop gently onto the nut from about 12 to 18 inches.
Once you've got the nut broken into 15 or 20 pieces, use your nut pick to pry the meat out.
It will last all winter long!
My aunt and uncle would spread them in the gravel driveway and just leave them for a week or two of getting run over. I used to wish they could grow pecans - that would have been worth it. But God or nature had black walnuts and persimmons growing there.
You could do the gravel driveway technique, or build a frame from hardware cloth and 2x6’s. Put the nuts in and allow the husks and stain to drain out the bottom of the frame, through the HW cloth. It’ll take several months, just as the driveway technique - but I think it is easier to find the nuts in the frame after an early snow than in the driveway. ;-)
As for cracking them: We found that hammers are counter-productive. A good machinist’s vise works much better. Better than that, after you get the husks off, put them in an oven at 250F for about an hour. After that, they’ll crack *much* easier.
BTW — the stain from the husks makes excellent wood stain. I’ve seen it used on regular walnut on gunstocks. Beautiful results. Add a little mineral oil with some paint thinner as a carrier.
There’s also wild pecan trees in NJ, not to mention low & high bush blueberries, red & black rasberries, blackberries, elderberries, etc. There’s food all over the place in NJ - and most people are utterly ignorant of it.