Rust in a cast iron skillet is generally not harmful if it is properly addressed and the skillet is reseasoned. However, it's important to note that prolonged exposure to rust or ingestion of rust particles is not recommended.
When a cast iron skillet develops rust, it typically indicates that the protective seasoning layer has been compromised, exposing the iron to moisture and oxygen. Rust itself is not toxic, but consuming large amounts of it can be harmful to your health. Therefore, it's crucial to remove rust from the skillet before using it for cooking.
To address rust in a cast iron skillet, follow these steps:
Scrub the rust: Use a scrub brush or steel wool to remove the rust from the affected areas. You can also use a mixture of water and mild dish soap for this step.
Rinse and dry: Thoroughly rinse the skillet with water and make sure to dry it completely to prevent further rusting.
Re-season the skillet: Apply a thin layer of cooking oil or solid vegetable shortening to the skillet's surface, both inside and outside. Place the skillet upside down in an oven preheated to around 350°F (175°C) and bake it for about an hour. This process helps create a new protective seasoning layer.
Repeat seasoning if necessary: Depending on the severity of the rust, you may need to repeat the seasoning process to fully restore the skillet's surface.
By properly removing rust and reseasoning the skillet, you can restore its usability and maintain its non-stick properties. Regularly seasoning your cast iron skillet and avoiding prolonged exposure to moisture will help prevent rust in the future.
Remember to exercise caution and use common sense when dealing with rusty cookware. If you have any concerns about the safety of a rusty cast iron skillet, it's best to consult a professional or consider replacing the skillet.