First, run a little water into the skillet and add a palm-full of kosher salt. Next, with a scrubbing pad, sponge, or pan scraper, scrub until the debris loosens. Rinse the pan with water.
Place the pan in the preheated oven, then turn the oven to OFF. Allow the pan to sit inside the oven for 1 hour. Remove from the oven. Allow it to fully cool before using.