Someone accidentally running your cast iron skillet through the dishwasher isn’t the end of the world. It’s annoying as hell but easily fixable. Most of the time you can get away with scrubbing the rust off with steel wool and soap- once the rust is removed, run the pan through a few rounds of seasoning. If scrubbing with steel wool isn’t enough (most likely the case of the skillet in this video), soak in a 50/50 water/vinegar solution for 40 minutes at a time. Once the rust is removed, run your