Scrub ham with a vegetable brush to remove any mold. Place in a large pot or in a sink with enough cold water to cover. Let soak 24 hours.
Preheat an electric oven to 350 degrees F.
Drain ham and scrub again with vegetable brush to remove any salt residue. Place ham in a large roasting pan with 5 cups cold water. Cover tightly with parchment paper and aluminum foil. Transfer to oven at 7:00 P.M. and increase temperature to 500 degrees F. Cook for 15 minutes and turn off the heat. At 10:00 P.M. turn heat on to 500 degrees F for 20 minutes, then turn off the heat. Remove the ham from the oven at 7:00 A.M. It is important to never open the oven door after placing the ham in it.
Note: It's important to stress the fact that this must be done in an electric oven and not a gas oven.
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