Knives, silverware, pots and pans can all rust if they are made of steel. Don’t worry, the rust is not dangerous and you can still safely use the knife. The only issue with rusted knives is that it is unsightly and can add impurities to your food preparation. Also, if rust is not treated, it can end up making a knife unusable.
Types of Steels and How they Rust
Steel is divided into two general categories: stainless and carbon. Carbon steel is made up of mostly iron with a small percentage of carbon and a few other metals. Stainless steel is made up of iron, chromium (about 15%), carbon, and a few other metals. The chromium surrounds the iron and protects it from being oxidized by oxygen. However, chromium reduces the durability of the blade–it’ll need to be sharpen more often than carbon steel.
Stainless steel is more resistant to rust than carbon steel but it does not mean that it is rust-proof. It can withstand moisture more than carbon steel but, with severe misuse, it can still rust. Only titanium and ceramic knives are 100% rust proof since they do not contain iron.
How to Prevent Rusting on Knives
- Do not wash your knives, pots, pans, and good silverware in the dishwasher. The extreme heat will cause the metal to expand and contract, causing stress points that can become the seeds to rust.
- Wash your knives after each use and dry them off. The oxygen in water can easily bond to the iron and this is the most common source of rust.
- Avoid salt water. If you are going to work in a salt water environment, use a titanium or ceramic knife.
Once a knife has rust, the rust can be removed but the knife will always re-rust in the same spots. It is best to prevent rust since removing rust is only a temporary situation.
How to Remove Rust from Knives
There are a few methods you can use to remove rust from knives. They will remove the sight of rust but the rust will never be cured. Basically, you need to use something that is acidic to free the oxidized iron from the rest of the metal.
With Lemon Juice
Take a lemon, slice it in half, and run one side on the rusted metal. If the rust is small, you can remove it with a scrubbing pad. If it is large, you might need to leave the lemon on the spot for 30 minutes before it will start falling off.
You can also soak the knife in white vinegar (apple cider vinegar might leave a stain) for 30 minutes. Afterwards, use a scrubbing pad to remove the rust.
Rust is best treated with prevention. Once rusted, a knife is forever scarred. You can remove rust spots by soaking a knife in a non-toxic acid like lemon juice or vinegar. This can be used on all types of knives from machetes to pink pocket knives.