Start a large pot of salted water boiling (1 tablespoon salt for each quart of water). Scrub and wash the hard-shell crabs. Handling with tongs, slide them one at a time into the boiling water. Reduce the heat to a simmer and cook for about 25 minutes.
To eat hard-shell crabs, use a sharp knife to remove both the carapace and tail flap by opening the tail flap on the belly and pulling it against the carapace. Discard the spongy material under the shell, and split the bodies, also discarding the gills, intestines and sandbags. Pick out the meat, using a nutcracker to open the claws.
Chill and nibble at will. Each crab will yield about one and one-half ounces of meat.
Take plenty of napkins!