I read the submissions regarding seasoning cast iron with interest.
Many years ago I was fortunate to buy a new Wagner Dutch oven that must have sat on the shelf for an appreciable amount of time; the price was under $20. Inside it had the instructions from Wagner for seasoning. The instructions called for the use of peanut oil in an oven at 375 degrees F. for one to two hours.
The only reason there is peanut oil in our house is for seasoning cast iron. Seasoning is not a once-and-done procedure, rather it needs to be built up over time and be renewed to protect the cast iron and produce the original non-stick cooking surface. There are times that everything needs to be stripped down to clean metal, and then re-seasoned.
Using fat from meat products has the potential to taint food cooked afterwards if handled improperly, especially if not rendered. Also, non-food products should never be used to season cast iron.
All cast iron cookware is made using sand molds and is porous. More or larger porosities in cast iron indicate poorer quality. Small imperfections are not unusual and can be troublesome, especially when exposing a pan to a high heat environment. Overly porous cast iron will be difficult to clean and season properly. Dropping cast iron, especially when hot, may be the end of that pan. Foreign cast iron tends to be junk, with exceptions from the Scandinavian countries.
For cleaning, never put cast iron in a dishwasher with modern soaps. Porosities in the surface tend to hold soap and contaminate whatever is cooked next in the pan. It is imperative to rinse all cast iron when using abrasive cleaners, like Comet, or scrubbing with steel wool, before seasoning. I place my cleaned cast iron upside-down in a pre-heated oven to prevent thick build-ups of oil flowing into the bottom of the pan.
I have tried many methods for bringing old cast iron back to life and prefer media blasting to remove old seasoning, followed by cleaning thoroughly with boiling hot water, then seasoning using Wagner’s instructions.
When I begin to see silver in the pan, small black flakes in cooked food, or worse (rust), I scrub my cast iron using boiling water without soap, and then I re-season.
Good cast iron which receives care should last more than one lifetime. – D.