Just thinking ~ a hickory nut with full husk ~ that'd be the ticket. Now that's a plant product you don't want to try messing around with ~ you start picking them off the ground around the tree too soon one of the others might drop on you like a mortar round. Then, if you try pulling off the husks you'll get a robust tan on your hands.
Best to find a gravel driveway, toss them out, and drive back and forth on them.
This is a plant that cries out for iron and steel!
Having had hickory trees, and having cleaned what seemed like tons of nuts fresh off the tree to get what was only pounds of nut meat - let the squirrels eat those things, then shoot the squirrels.