Clean rust from cast iron by washing it with soap and water, heating the metal, adding vegetable oil and salt, and rubbing with a paper towel or newspaper. Replace the salt and oil as necessary, and wipe the pan clean. Prevent rust from forming again by seasoning cast iron.
It is often possible to find cast iron cookware at garage sales or thrift stores. Unfortunately, much of what is available is rusted. Because of the durability of the product, cleaning the rust and seasoning the pan provides you with cookware that can last a lifetime. Salt and oil work together to remove the rust without using dangerous chemicals to do the job.
Seasoned cast iron provides a nonstick cookware that does not peel into foods. To season the cookware after cleaning, heat the pan on the stovetop over medium heat, pour a small amount of oil into the pan, and tilt it to ensure you coat all the surfaces in oil. Leave the pan on the heat for five minutes, and pour off the excess oil. Place the pan in an oven set at 300 degrees Fahrenheit for 1 1/2 hours.
While cast iron is durable, it rusts with exposure to moisture. Many cooks recommend heating cast iron cookware on the stovetop after washing it to remove the excess moisture before drying.