Years ago (at different times), I bought two cast iron frying pans, one made in the US and one in China. At the time, I did not know that new cast iron wares need to be kashered. (In fact, I thought that the fact that they came with instructions that they must be seasoned was proof that no oil or fat had been put on them by the manufacturer.) So I went ahead and seasoned them according to instructions: spread oil on the pan, put it onto a piece of foil inside the oven, and heated the oven to the recommended temperature. (The US-made pan has the instructions engraved on the bottom, so I can tell you: 300 degrees F for one hour.) Since then, I have used those pans a number of times. (Actually, I have not used the China-made one in about two years, if that matters.) Recently, I found out that new cast iron does have to be kashered before it is seasoned and used. At this stage, do I still need to kasher these frying pans before using them next? If so, how to do it? One of the sources that said that it needs to be kashered said to put the pan into the oven and put the oven on the self-clean cycle. That does not help me because my oven is not self-cleaning. I saw another source (now I cant find it again) that said to cover the pan with charcoal and set it on fire (of course, outdoors in a safe place, as if it were a campfire). If so, would the pan have to become red hot, if this is even possible? (Since we are talking about cast iron and not stainless steel, I am confident that the pan would survive the experience.) Or is something different appropriate now? Thank you.

ב"ה Shalom Undoubtedly, one the reasons the Rabbis said in Pirke Avot to choose a Rabbi and keep away from uncertainty was to avoid the confusion you seem to be facing. In any case, it is not clear that actual oil from non- kosher animals is spread on new pots. Many are of the opinion that mineral oil is used, therefore the pots would not require koshering at all. In any case, to be cautious and avoid doubt you should boil the pots in boiling water or at least pour boiling water over them . All the best