It is not advisable to bake with an old and rusty cast iron pan without addressing the rust issue first. Rust can negatively affect the taste of your food and potentially cause health concerns. However, if you properly restore the cast iron pan and remove the rust, you can continue to use it for baking. Here's a general process to restore a rusty cast iron pan:
Scrub the Rust: Using a stiff brush or steel wool, scrub away the rust from the pan's surface. You can also use a mixture of water and mild dish soap for added cleaning power. Make sure to scrub thoroughly, covering all the rusty areas.
Rinse and Dry: Rinse the pan under warm water to remove any loose rust particles. Dry it thoroughly with a towel to prevent further rusting.
Remove Stubborn Rust: If there are stubborn rust spots that didn't come off with scrubbing, create a paste using equal parts baking soda and water. Apply the paste to the affected areas and scrub gently. The baking soda acts as a mild abrasive to help remove the rust. Rinse and dry the pan again.
Season the Pan: Seasoning is an essential step to protect the cast iron and create a non-stick surface. Apply a thin layer of cooking oil (vegetable oil or flaxseed oil are commonly used) to the entire pan, including the handle and outside. Make sure to coat all surfaces evenly.
Bake in the Oven: Preheat your oven to a temperature between 300-350°F (150-175°C). Place the cast iron pan upside down on the oven's center rack with a baking sheet or aluminum foil on the lower rack to catch any drips. Bake the pan for about one hour.
Cool and Reapply Oil: Turn off the oven and let the pan cool completely inside. Once cooled, you can repeat the seasoning process by applying another thin layer of oil to the pan's surface.
Regular maintenance and seasoning are key to keeping your cast iron pan in good condition. After each use, clean the pan gently with a brush or sponge (avoid harsh soaps) and dry it thoroughly. Apply a thin layer of oil before storing it to maintain its seasoning and prevent rust.
If you find that the rust is extensive or the pan is severely damaged, it may be best to seek professional help or consider replacing the pan to ensure safe and enjoyable baking experiences.