Step 1Mix together the flour, salt and pepper to taste in a large bowl.
Step 2If you haven't purchased cleaned crabs, clean them: With kitchen scissors, cut off the "face" about one-fourth inch behind the eyes. Gently probe the opening with the tips of the scissors and, if there is a gray-black sand sac, remove it. Lift the points of the shell on either side and cut away the pale gray finger-shaped gills underneath. Turn the crab over and cut away the loose apron folded underneath. As each crab is finished, put it in the bowl of flour.
Step 3In another large bowl, stir together the eggs and milk until thoroughly blended.
Step 4Turn the crabs in the flour until completely coated. Lift them out and gently shake loose any excess. Turn them in the egg-milk combination until completely coated and then return them to the flour mixture, turning over to coat them again. Gently shake loose any excess flour and arrange the crabs on a baking sheet lined with wax paper. Refrigerate at least 30 minutes.
Step 5When almost ready to serve, heat one-fourth to half an inch of oil in the bottom of a heavy skillet. The oil is hot enough when a piece of crust-less bread touched to the surface sends up a rapid, steady stream of bubbles. Place the crabs in the pan, arranging them so the claws are tight against the body. Fry until nicely browned on one side, then turn and fry the other side. This will take about 4 to 5 minutes per side. The oil should be fiercely bubbling the whole time.
Step 6When the crabs are cooked, remove to a baking sheet lined with paper towels or a brown paper sack to drain. Serve each crab with a generous tablespoon of homemade sauce tartare and pass the rest.