Don't Use Soap on Cast Iron
Although cast-iron pans look tough, they can be high maintenance: The conventional wisdom is to avoid washing them with soap, not to put them in the dishwasher and not to let them air dry (use a towel or they'll rust). Those last two rules are important to follow, but George Duran, Chef Ambassador for the cookware company IMUSA, says if a pan is well seasoned, it's fine to wash it in cold water or with a little bit of soap. The oil you used to season the pan should prevent the cleaner from penetrating too deeply. Duran also shared this nugget: Use kosher salt to scrub off sticky residue, then re-season the pan by heating it in a warm oven and rubbing it with oil.