How do I reseason my cookware?
While maintaining the seasoning should keep your Cast Iron in good condition, at some point you may need to repeat the seasoning process. If food sticks to the surface, or you notice a dull, gray color, or rust, repeat the seasoning process:
Wash the cookware with hot, soapy water and a stiff brush. (It is okay to use soap this time because you are preparing to re-season the cookware).
Rinse and dry completely.
Apply a very thin, even coating of MELTED solid vegetable shortening (or cooking oil of your choice) to the cookware (inside and out).
Place aluminum foil on the bottom rack of the oven to catch any dripping, and set temperature to 350 – 400 degrees F.
Place cookware upside down on the top rack of the oven.
Bake the cookware for at least one hour. After the hour, turn the oven off and let the cookware cool in the oven.
Repeat the process as needed to achieve the classic black patina.
Store the cookware uncovered, in a dry place when cooled.
Check out this video of the process.