how to get rust off knife
Kitchen knives can rust if they are made of steel. Don’t worry, the rust is not dangerous and you can still use the knife safely. The only problem with rusty knives is that they are unsightly and can add impurities to your food preparation. Also, if rust is left untreated, it can end up rendering a knife useless.
Rust is the common name for a compound called iron oxide, that reddish-orange flaky stuff you see splattered on some metal. This forms when iron and oxygen react to moisture. It doesn’t even have to be water exactly, it could simply be the presence of water in the air, reacting with iron found in a metal.
There are several DIYs you can use to remove rust from your kitchen knife, ranging from using baking soda to using potatoes.
Read on to find out how you can easily deal with rusty knives.
Types of steel and how they rust
Steel falls into two general categories: stainless and carbon .
Carbon is mainly made up of iron with a small percentage of carbon and a few other metals. Stainless steel is made up of iron, chromium (approximately 15%), carbon, and a few other metals. Chromium surrounds iron and protects it from oxidation by oxygen. However, chrome reduces the blade’s durability; will need to be sharpened more frequently than carbon steel.
Stainless steel is more resistant to rust than carbon steel, but that doesn’t mean it’s rust proof. It can withstand moisture better than charcoal but, with severe misuse, it can still rust.
Only titanium and ceramic knives are 100% rust proof as they have no iron.
Why do knives rust?
These are the ingredients for rust: iron (metal), water, and air.
For those who don’t know, iron is the secret ingredient in the steel found in your knife blades. So when you combine your knife with air and water, it rusts you.
Kitchen knives rust when you leave them damp for a while. For example, keeping a badly dried knife.
How to prevent rust on knives
- Do not wash your knives in the dishwasher. Extreme heat will cause the metal to expand and contract, causing stress points that can cause the seeds to rust.
- Wash your knives with dish soap after each use and dry them. Oxygen in water can easily bind to iron and this is the most common source of rust.
- Avoid salt water. If you will be working in a saltwater environment, use a titanium or ceramic knife.
- Do not soak your knives or leave them in water overnight. Water speeds up the oxidation process and reduces the life of your knives.
How to remove rust from a knife
There are a few methods you can use to remove rust from knives. They will take your eyes off the rust, but the rust will never heal. Basically, you need to use something acidic to free the rusty iron from the rest of the metal.
1. Use lemon juice
You may have known lemon as a great product to use when you are cold or to apply to a freshly cut fruit like avocado to prevent oxidation and browning. Apart from that, lemon is a great alternative that you can use to remove rust from your kitchen knives.
The natural citric acid in lemon juice is responsible for removing rust.
Take a lemon, cut it in half and run one side over the rusty metal. If the rust is small, you can remove it with a scouring pad. If it’s large, you may need to leave the lemon in place for 30 minutes before it starts to fall off.
If the rust was severe, you can carefully use a piece of steel wool to clean it and get rid of it.
2. White vinegar to remove rust
Vinegar is one of those kitchen essentials. It is known as a natural cleansing agent with antiseptic properties. White vinegar also contains 5-6% acetic acid, which is a weak acid.
The properties of acetic acid in vinegar will remove rust in a simple and direct way.
You will only need to soak and leave the knife in white vinegar for 30 minutes. Then use a scouring pad or steel wool to remove the rust, especially if the rust has been building up for a while.
If it is a freshly rusted knife, after soaking it in vinegar, just use a soft cloth or towel to clean. You should not use apple cider vinegar as it is likely to leave rust stains on your knives.
3. Baking soda
In the baking soda method, you will need to create some baking soda paste. You can pour a good amount of baking soda into a container and add some water. Stir until it becomes a paste.
Apply the thick baking soda paste to a toothbrush and apply it generously to the blade. You can just scrub with the toothbrush if the rust isn’t too severe or hasn’t settled.
For extremely rusty blades, you’ll need a little more abrasion to help remove the rust. Steel wool is commonly recommended, although it can damage the blade if you rub too hard. Another alternative is a slightly abrasive sponge.
Be careful not to scrub too hard because you can scratch the blade or ruin the finish.
Finally, wipe the blade clean with a cloth to remove excess baking soda. If you want to be really good with your blade, you can apply a little oil afterwards to make sure it’s lubricated and protected from rust in the future.
4. Rust removal with citric acid
Another way to remove rust from your kitchen knife is by using citric acid. This is a common product that you can buy at health food stores or supermarkets. It is quite effective in removing rust.
The process for removing rust is simple: add about three tablespoons of citric acid to a bowl of hot water, dip the knife in, and leave overnight. The next day, all you have to do is remove the newly dissolved rust.
The main downside to using citric acid is that it removes rust along with other coatings or paint on the knife. But if your knife is just stainless steel with rust, then it is a great method to successfully remove rust on kitchen knives.
5. Metal Glo to remove rust
Metal Glo is a popular chemical solution that can use stubborn rust on your carbon or stainless steel kitchen knives.
It’s a carefully formulated solution that’s safe for cookware, cutlery, knives, or even jewelry.
When using metal gloves or any other chemical solutions on kitchen knives, rub them along the grain pattern to avoid the possibility of scratching the metal.
Apply the thick glo metal paste evenly on the metal part of the knife.
Natural ways to remove rust from kitchen knives
When you don’t have the materials around the house to remove rust from your knife, there are some natural methods you can use.
1. Potato Method
Certain foods also act as a good source for rust removal and using potatoes is one of the natural methods to remove rust.
The potato is a very effective food to remove rust due to its oxalic acid.
Simply stick your knife in the potato for a few hours, to allow the oxalic acid enough time to remove rust from your knives.
After removing from the potato, clean the blade with oil and the rust will be gone. To prevent rust in the future, you should consider applying oil to your knives, especially when storing them for long periods of time.
One thing to keep in mind is that the potato method can be a great way to remove rust when it’s not much. With rust that has been left for a while, you need to consider more effective ways than just potato. Maybe combine with dish soap.
2. Onion Method
Onions are another food that helps remove rust naturally. If you cut an onion from one side to the other, the rust will start to come off on its own.
The sulfonic acids in onions are the key ingredients to clean the blade and remove rust stains.
Things to know when removing rust from knives
1. Prevention is always the best method
If you can prevent your knives from rusting in the first place, that’s the best approach. You will only need to maintain, apply some preventive measures and you are good to go.
For example, it is helpful to apply a little mineral oil from time to time. Mineral oil will keep rust at bay, even when you store the knife for long periods.
2. Protect your knife blades
Before choosing cleaning products for your rusty knife, make sure you understand the implications this can have on your knife blade. If it manages to remove the rust, but scrapes the blades and renders them unusable, you’ve lost it.
Look for methods that clean your knife and also protect the knife blade. Vinegar is a great option, not to mention that it also has antiseptic properties, which makes it amazing for your kitchen.
3. Some rust stains can be irreversible
While there are several methods you can use to remove rust, you also need to understand that some rust stains are permanent. If you’ve left your pocket knife for months and it has high levels of rust, it can be difficult to get rid of rust stains successfully and buying a new one may be the best alternative.
4. Blade type and brand matters
Before choosing a rust removal method, make sure you understand the type of material used and how it interacts with various products. For example, using dish soap and the potato method, along with scrubbing with steel wool, can give great results on one knife and not another.
As such, don’t do anything because you saw it with a friend, do your research and make sure he can remove the rust from your knife. But some products like vinegar and soda baking powder are safe and gentle on blades, most of the time.
5. A rusty knife can be a health hazard.
Rust from a knife introduces harmful elements into food as it exposes the metal and leaves it to get into the food during preparation. As such, you need to be quick to remove rust from kitchen knives and use the most appropriate method, for example baking soda.