Scott Mayland quoted:
The way my grandmother cleaned her pans was to build a fire out doors and put the pan in the fire and burn it clean. this can be done in a fire place as well.
And the upside to this method is that with the same fire, you can 'cure' it. Build your fire; put the pan in it and leave it in until it turns white(the gummy blackstuff turned to ash). Remove it; and let it cool. Once it is cool enough to handle; coat it with lard and reheat it, but don't burn it. Repeat the lard coating and baking several times or until it is smooth and shiney. Once it is cured *never*, absolutely never, use soap on it or you will have to cure it all over again. Just wipe it out with a cloth or paper towel, and it is ready for the next cooking. If you have to boil water in your cast iron, it will have to be cured afterwards because that will 'cook' the oil out of the metal and things will stick to it. Just ask me. I've used cast iron all my life and right now I have 12 cast iron pans, two pots and two lids. A couple of weeks ago, the landlord stopped by on his way to the garbage dump to see if there was anything in the load I might want. I spied an old cast iron fry pan and pulled it out. It was all rusted and nasty. He said it had laid out back of his shop for a couple of years in the dirt. I just used it this morning to fry my eggs and bacon in. Properly cured cast iron is slicker than teflon.