Old rusty cast-iron pots and pans can still be used for cooking, but it depends on the extent of the rust and the condition of the cookware. In some cases, they can be restored and used safely, while in others, it might be best to discard them. Here's what you should consider:
Surface rust: If the cast-iron cookware only has a thin layer of surface rust, it can typically be restored and made safe for cooking. Surface rust is usually superficial and can be removed through proper cleaning and re-seasoning of the cast iron.
Deep rust and pitting: If the rust has penetrated deeply into the cast iron or has caused significant pitting, it may be challenging to restore the cookware properly. Deep rust and pitting can create uneven surfaces, making it difficult to maintain a smooth cooking surface.
Health concerns: Rust is not itself harmful, but it can be a breeding ground for bacteria. If the rust has caused significant damage to the cookware and proper cleaning and seasoning can't restore it adequately, it's best to err on the side of caution and avoid using it for cooking.
Leaching iron into food: Cast iron leaches a small amount of iron into the food, which is generally considered beneficial for most people. However, when cast iron is heavily rusted or damaged, it may leach more iron than usual, which could be a concern for people who need to limit their iron intake.
If you want to try and restore a rusty cast-iron pan, you can follow these steps:
Scrub off the rust: Use steel wool or a stiff brush to scrub off as much rust as possible from the surface of the pan.
Clean the pan thoroughly: Wash the pan with warm, soapy water to remove any remaining rust particles and debris.
Re-season the pan: To re-season the pan, coat it with a thin layer of vegetable oil or solid shortening and bake it in the oven at a high temperature for about an hour. This process helps to create a non-stick surface and prevent further rusting.
After re-seasoning, the pan should be smoother and ready for use. However, if the rust is extensive or the pan is severely damaged, it may be best to replace it to ensure safe and reliable cooking. Always inspect your cookware regularly and take proper care of it to prevent rusting and extend its lifespan.