pba: why did you wake up now? what have you been doing for years with your aluminum foil etc? do you think it comes from the ground so nice and shiny, and only on one side? foil, stainless pots and pans etc, they’re all greased! do nothing!
the grease is likely petroleum based. and if not, likely vege. it is Nifsal me’achilas kelev and eino ben yomo. it is also applied at a higher temperature than libun chamur, i am told by a frum yid in the steel business and a mashgiach kashrus.
don’t worry, just toivel the pan and use it in good health