How to properly re-season a carbon steel pan?

To properly re-season a carbon steel pan, first wash it with hot water and a soft sponge to remove any food residue. Dry the pan completely, then apply a thin layer of oil (such as vegetable oil or flaxseed oil) to the entire surface, inside and out. Place the pan upside down in a preheated oven at 400F for about an hour. Let it cool in the oven before removing. Repeat this process a few times to build up a good seasoning layer.