@moko How do you kasher a cast iron pot that is seasoned with possibly treif oil? Does it need libun gamur, libun kal, or nothing?
there are differences of opinion on this matter. If it is seasoned with kosher oil then no kashering is necessary. I would be happy to provide hashgacha if Lodge is interested.
It comes down to 2 factors:
1. Rama Mpano- if the oil is treif , even if you had a lot of oil on the pan it would require kashering
2. What constitutes the din of machvas. How much liquid is needed. I believe conventional wisdom is that you need enough liquid for frying. But others hold as long as it is more than a coating such as Pam , it would qualify as a machvas and then be subject to that machlokes. Even though normally machvas from treif would require libun, others believe that this is at best a safek and hagala would be sufficient.