What's the best way to season a cast iron skillet?
First, there is no difference between seasoning and re-seasoning, unless you need to do some extra work to remove rust (see instructions below). In fact, for new cast iron, scouring is also usually a good idea since you need to get off whatever wax or protective oil the manufacturer or seller may have put onto the cookware. (They don't use cooking oil for that sort of thing, believe me.)

If you need to remove rust: use a mixture of salt and oil and scrub that hard into the rust, then rinse thoroughly in hot water. Use steel wool if necessary.

Next, scour the pan completely under hot water. Do this for several minutes or until the water runs clean. I've heard varying things about whether soap or an SOS pad is OK at this step. My personal opinion is that it's OK, but you must wash the soap completely off before continuing with the seasoning so that your seasoning doesn't taste like soap!

Coat the cookware with grease or oil. (I do this with the whole pan, not just the cooking surface, to reduce the possibility of external rust.) Crisco, vegetable oil, and lard all work well. Don't pick something with a low smoking point, or too strong a flavor. Make sure it's a light coating... you shouldn't have pools of oil anywhere on your cookware.

Bake your skillet in a 250 - 350 °F (121 - 178 °C) oven for an hour. If you used liquid oil, you may want to put the cookware in upside down so excess oil drips off. But it's good to put a cookie sheet or something underneath the cookware to catch the drips if you do!

Let the cookware cool, and wipe off any excess oil.

For best results, do this two or three times, though a skillet can be satisfactory after a single treatment.


To keep the seasoning happy:

Don't let the cast iron sit too long without using it (you may notice a rancid smell or flavor if the seasoning turns bad; I'm not sure at what point this happens, but it's happened to me before).

Don't cook anything acidic (e.g. tomatoes) during the first or second use of your pan.

Don't use dishwashing liquid or soap on the pan (hot water and scrubbing only).

After cleaning the pan after each use, wipe it lightly with another bit of oil, using simple vegetable oil.


Another trick sometimes used to season Chinese woks: rub Chinese chives over the surface of the cookware when the oil is being heated (this works best on a stovetop, not in the oven). The juice of the chive has sulfur compounds that help remove remaining flavor from the previous coating of the cookware. Be aware that this technique really kicks up a lot of steam and smoke. I've never tried it on cast iron skillets, but I'd be curious if anyone out there has.