Things You'll Need
Since the 1600s, cast-iron pans have been used for cooking foods on stovetops or over a hot fire. Cast iron, however, has porous surfaces where water can gather and start the rusting process. When the pan is seasoned, the process seals porous surfaces to block water and food particles from seeping in, preventing rust from forming and bacteria from building up.
Use the scrub brush to clean the surfaces of the pan inside and out with hot water. Do not use soap on the frying pan, leave it to sit with food in it for long periods or place it in a dishwasher. Wash the cast iron as soon as you are done using it.
Place the pan on the stovetop with the flame on low or on an electric stove with the heat set as low as possible. The pan will dry over the heat. You can dry the pan with a towel, but you will need to be thorough in drying the pan inside and out. Allow the cast-iron pan to cool after heating.
Pour vegetable oil on a paper towel and rub the inside and outside of the pan. Coat every inch of the pan in a thin layer of oil.
Place the pan in the oven at 350 degrees Fahrenheit and bake for an hour. Turn off the oven and allow the pan to cool in the oven for at least two hours. Place the pan on the stovetop over medium to high heat about 10 minutes to darken the bottom of the pan. Turn off the heat and let the pan cool.
Store the pan in a dry location until you are ready to use it again.
If you must use soap the next time you wash the pan, it will need to be re-seasoned before storing away or rust will form.
For stubborn rust, sprinkle baking soda on a raw potato and rub away rusty areas, reports the website The Kitchn.