In the oven The best way to reheat a baked potato, so it crisps up again, is to bake it in the oven. Set the oven to 350 degrees f. Place it in the oven, directly on the rack for 15-25 minutes. In an air fryer You can also heat them up in an air fryer. Set the air fryer to 350-400 degrees. Place them in the air fryer basket and heat it for 3-5 minutes, or until it's warmed through. In a microwave This is the worst way to heat up a potato, since it will result in gummy potatoes. But if you don't mind the texture and just want it to be quick, heat them up this way.