Preheat the oven to 425°F. Scrub any number of potatoes with a vegetable brush. Pat dry with paper towels and place on a pie plate or other shallow baking dish (I keep an old metal pie plate just for baking potatoes). Prick the skin in a few places with a fork to prevent bursting. (Do not wrap the potatoes with foil, which steams them and prevents the skins from crisping.)
Bake the potato(es) until the pulp is tender when poked with a knife and the skin is becoming very crusty, 1¼ to 1½ hours. Cut a cross in the top of each potato. Covering your hands with a kitchen towel, grasp each end and gently push toward the center to pop open the top. Serve hot.