How do you season/use/clean Cast Iron?

I always rub mine in Crisco or lard and throw in a hot fire. You can also do it in a oven, but it will smoke up the house. I have 7 cast iron skillets and I wash the one that I fry chicken in, but I dry it very very well. (never let one air dry or put in a dishwasher). I also put a lite coating of grease on it after each use. The skillet that I only cook cornbread in, I never wash it, just wipe it out with a dry paper towel.

Use steel wool (not the kind with soap in it, just plain steel mesh) to scrub off the rust. I use olive oil on mine. For the first time, I use the oven so I can season the inside and rust proof the outside. Coat inside and out lightly with oil and bake. 

After that, you should only need to worry about the inside.

I NEVER use soap to wash mine. Just hot water. After I wash it, I put it on a stove burner, turn it up high until it's dry. 

Let it cool, put a thin layer of oil all over the inside, turn the burner back up to high and turn it off when it starts to smell like hot oil.

After enough uses, you'll have a non-stick surface that's better than Teflon.

I use mine for pretty much anything that doesn't involve boiling. 

I've always done mine this way. One of my skillets was my grandmother's and is older than I am, and still in use. 

I have an old one cast iron skillet that I bought rusty at a garage sale and I have been trying to season for years.  I still struggle with food sticking to it occasionally.  I mostly cook meat in there now. I gave up on trying to make pancakes in there.

I have a smaller one that came pre-seasoned and I LOVE it. 

To add to the other comments, I have found that if you have food stuck to the bottom, instead of reaching for soap and a scrub brush, I simply fill the skillet with a little water and heat the water to boiling.  The heat and the water usually dislodge most of the food.  Whatever is still stuck on the bottom of the pan I can get off with a metal spatula.