Not if you have all the inside info! The secret is that you do most of the work by gently scraping off all residue from the pan.  If necessary, you can run it under water with a gentle scrub with some salt or any non-metal scouring pad. You might have read elsewhere that soap is a no-no, but it’s actually ok to use as most soaps nowadays are a lot less harsh than the lye-based soaps used previously! If you’ve used water, you’ll want to dry your pan thoroughly and if you want to be extra thorough, heat it on medium heat to get rid of any remaining moisture.  If you’ve used soap, you’ll want to first dry your pan, then use a tiny amount of oil to coat the inside again. To prevent the oil from going rancid, reheat the pan to allow the oil to carbonize/polymerize with the pan. If you’re using your pan regularly, once a week of this is more than enough! Our pan is reserved for all the dry stuff- so we don’t do anything more than a few gentle scrapes!  This might scare you into thinking it’s unhygienic- is not! As long as the pan is dry, microbes won’t grow, and heating the pan will get rid of any moisture. No matter what, never soak a cast iron pan! This won’t ruin it, but the moisture will break down the layers of seasoning you’d have built with so much love!