Wash the skillet with hot water and a small amount of mild soap
Scrub off rust, old residue, or flaking seasoning with a stiff brush or steel wool
Rinse thoroughly
Dry completely with a towel
Heat the skillet on the stove or in the oven until all moisture is gone
Apply a very thin layer of high-smoke-point oil to all surfaces, inside and out
Wipe off all excess oil until the skillet looks nearly dry
Place the skillet upside down in an oven at 450–500°F
Put foil or a baking sheet on the lower rack to catch drips
Bake for 1 hour
Turn off the oven and let the skillet cool inside
Repeat the oiling and baking process 2–4 times for a stronger seasoning
Store the skillet in a dry place
Lightly oil after each use to maintain the seasoning