Foil potato can be baked in the oven or in the embers of a campfire, grill or fireplace. Preheat oven to 225° C. Wash, brush and dry three potatoes of the same size. Thinly brush three pieces of aluminum foil with oil. Wrap the foil potatoes tightly in it. Place the foil potatoes on a wire rack. Bake on the middle shelf for 45 minutes. Lightly break apart the foil potato with a fork. Season with salt. Serve with herb butter.