https://www.cnet.com/pictures/season-your-cast-iron-pan-the-right-way/
This skillet cries out to be re-seasoned
This cast-iron skillet has seen a lot of action. Inside its cooking surface are lots of deposits from carbonized oil that will make delicate food stick. To remedy the situation, it's time to clean it out and re-season the pan.
Add a little water
First add an inch or two of water into the skillet.
Simmer for a few minutes
Next turn on the stove and bring the water to a soft boil. Let it simmer for a few minutes to loosen bits of debris and stuck-on junk.
Pour out the pan
Turn off the stove and pour out the water. Remember, this pan is hot and so is its handle. Always use a pot holder to avoid serious burns. Then, set the skillet aside to cool down a bit.
Don't fear the dish soap
Once the pan is cool enough to handle, Grab a steel wool pad, and smidgen of mild dish soap. Yes, it's OK to use soap and abrasive wool when re-seasoning a cast-iron pan.
The idea is to remove the stuck-on bits, then create a smooth layer of seasoning.
Scrub with steel wool
Don't be afraid, scrub that skillet!
Wash out the gunk
Take your scrubbed pan to the sink and wash it in warm water.
Dry out the pan
Now dry the skillet with a towel, then place it back on the stove. Fire up the burner to medium and heat the pan for 5 to 10 minutes. The point is to evaporate any lingering moisture.
Use some canola oil
Turn off the stove and let cool until it's still warm, not cold. Next add about a tablespoon of canola oil. You can also use a solid shortening like Crisco.
Rub in the oil
Grease the inside of the pan gently with a paper towel or lint-free cloth.
Oil the entire pan
Don't forget to oil every part of the skillet, including the sides and bottom -- even the handle. Cast iron cookware is made from a solid piece of iron. Every inch should be protected from moisture and rust.
In goes the skillet
Place your cast-iron pan into the preheated oven. Make sure to drop it in upside down so oil doesn't pool as it melts. Put an empty baking sheet on the rack directly below the pan to catch any drips.
Run the oven for 45 minutes to 1 hour. Then let the pan cool completely in the oven undisturbed.
Outdoor grills are a fine alternative
Seasoning tends to create some smoke or at least odd odors. Another way to go is to use an outdoor grill. That way, any unpleasant smells stay outside.
Don't let the heat levels get too high, though. Above 600 degrees F (315 degrees C) risks burning your oil seasoning right off.
Smoothly seasoned for duty
This pan is now much smoother inside and ready for action. The more you use it, though, the smoother and slicker the interior will get.
At this point, avoid abrasive pads and cooking highly acidic food. That will pull the season off, forcing you to repeat the process.
A trial run under fire
To test my revamped pan, I got it screaming hot in the oven (500 F).
I then carefully placed it on the stove (using a heat-proof pot holder), added a bit of oil and fired the burner up to medium-high.
Test steaks in the pan
With two steaks handy (New York strip and rib eye), I added them into the hot pan.
Oh, that cast iron sear!
Two minutes later I flipped my steaks over. What I saw warmed my heart -- nicely browned crust -- the hallmark of a well-seasoned cast-iron skillet.
https://www.cnet.com/pictures/season-your-cast-iron-pan-the-right-way/