There are a few tools that every cook should have in their kitchen - a great seat of knives, a heavy-duty stand mixer, a food processor, stainless steel nesting mixing bowls, a dutch oven, and a cast iron skillet.
Cast iron is one of those things that people either LOVE, or it scares the beejesus out of them because they don't understand it. The reasons against cast iron are that:
1) "it rusts"
2) "they're heavy"
3) "I don't know how to use it."
The reasons FOR cast iron far outweigh the reasons against it:
1) they're durable. It's not uncommon to find people using the pans they inherited from their granny.
2) many are made in the USA (Lodge brand)
3) they distribute heat evenly. And you can (and should) cook on lower heat using cast iron. Lower heat = lower energy bills.
4) they can help add iron to your diet
5) they cook food beautifully. Roasted veggies and cornbread are 100% better when cooked in cast iron than something else.
6) they can go from stovetop, to oven, to hell - a campfire if necessary
7) my favorite - once properly seasoned, you don't REALLY have to wash them. Oh how I love anything that doesn't require me to do additional dishes!
We have a 12 inch skillet that we received for Christmas a few years ago. I learned more about cast iron from screwing up with that skillet than anything. That sucker is also huge and not what I was necessarily looking for in an "everyday" skillet.
Friday I was at Goodwill, and an (I think) 8 inch skillet pretty much leaped off the shelf trying to get my attention. It practically yelled "buy me Sarah, buy me!" But at $14.99 for a rusted cast iron skillet when I could buy a new one for that price didn't tickle my fancy. Until I saw its blue tag. Friday was blue tag day, so it was 50% off! I snuggled that now $7.50 skillet to my overly nursed bosom, and promised to take it home and give it the kind of life it truly deserved.
Poor, poor rusty skillet. Someone didn't love you and/or know how to use you.
Is it just me, or does the rust stain look like a map of the Hawaiian islands? Just me? Ok...
First things, first, I cleaned the skillet with soap and water. In my humble opinion, this is one of the last times your skillet should need soap.
Then give it a 10 minute steam bath in a 300 degree oven.
When it is mostly dry, remove from the oven and pour a puddle of oil (I used olive, but any kind will work) and a generously helping of kosher salt in to the center.
In the same section as table salt
Using a rag you don't mind getting dirty, paper towels, or pieces of newspaper, work the oil and salt in to all parts of the skillet. Pay special attention to the rusty areas.
Those are scars on my knuckles. I'm 30 and do not have liverspots. Yet.
Then, rinse off the skillet, and put back in to the oven until it's somewhat dry-ish.
Put it on the stovetop on medium heat with another puddle of your oil of choice and work it around with another rag. I use a pastry brush. Let it heat and "cure" for about 5 minutes. Careful, the oil will be hot!
Pour the oil off, and put just a dab of high-heat oil in the skillet. Some people prefer vegetable oil for this part. I'm not a veggie oil fan - including canola - so I used a dab of bacon grease. You could also use coconut oil, or ghee I guess. Let the bit of oil melt/get hot, and then work it around to cover the entire surface of the skillet. Then, using a paper towel or piece of newspaper and remove all excess oil from the pan. Bake for 90 minutes at 300 degrees.
After round one in the oven:
Then, repeat the bit of oil, rubbing it around, and removing all the excess grease and bake for another 90 minutes at 300 degrees. And if I have to warn you that the pan will be really hot when you're doing it, I think you might have bigger issues than a rusted cast iron pan...
After round two in the oven:
You can keep adding oil and baking as many times as you want. After two times, this skillet was ready for its big debut in my kitchen. It made perfect eggs the next day.
Quick and final note on cast iron. No matter how much seasoning you give it, you'll always need a pinch of fat (butter, oil, shortening, etc. It kind of goes without saying that I wouldn't recommend cooking spray...) in a warm pan prior to adding food to it. I always add a sliver of butter to the hot pan prior to cooking eggs.
May your thrift store adventures bring you a cast iron gem of your own. The rusty and ugly ones need/deserve our love and help too. Why Sarah McLaughlin hasn't done sad commericals about the plight of injured cast iron is beyond me.