Clean your cast iron pan immediately after use. Pour hot water into the cast iron pan and let soak for no more than 2 minutes. For extra big messes, use boiling water.
Pour out water and wipe out any large food particles with a paper towel.
Add a couple tablespoons of kosher salt to the pan and scrub with the brush. Add water as needed to create a paste. Continue to scrub until clean.
Rinse out pan and dry well with a paper towel.
Place a small amount of oil in the pan and buff out with a paper towel.
Recipe by at https://www.adventuregathereat.com/methods-how-i-naturally-clean-cast-iron-pans/