How To Clean Carbon Steel Knives to Make Them Look Brand New

Carbon steel knives are popular among professional chefs and cooking enthusiasts due to their exceptional sharpness and edge retention. Due to the high carbon content, the blades of carbon knives are endowed with increased hardness, allowing for a thinner and sharper grind.

However, unlike most kitchen tools, carbon steel knives can rust over time, as they come into contact with oxygen and moisture. Cleaning and maintaining them is essential to ensure their longevity, performance, and safety.

While you can use a simple combination of lemon and salt or vinegar for general cleaning, you’re better off using a dedicated cleaner when it comes to removing rust and corrosion. We’ll teach you all this and more in the following guide!

Method 1: Using A Dedicated Knife Cleaner

The most convenient and effective way to clean your carbon knives is by using a dedicated knife cleaner that is formulated to remove rust stains. One popular cleaner that worked wonders in our tests was Bar Keepers Friend Cleanser. 

This particular cleaner is highly regarded for its effectiveness in removing tough stains and rust from various types of kitchen utensils, including carbon steel blades. Additionally, it offers the benefit of being versatile as it can also be used to clean other kitchen utensils and surfaces. 

There are also other off-the-shelf cleaners that you can choose from. However, it’s best to ensure that they are bleach-free, don’t contain other harsh chemicals, and are effective at removing rust and corrosion.

Cleaning Instructions:

1. Pour the cleaning solution onto the blade of your carbon steel knife, with a special focus on the rusted areas.
2. Rub a wet sponge across the blade and product before leaving it to work for 5 – 10 minutes. The rust should start to lift off from the carbon steel blade. 
3. Rinse off the product and dry the knife with a microfiber cloth. 
4. Repeat the first three steps if rust stains are still present. 
5. Dry it again with another microfiber cloth to ensure it is entirely free from moisture before storing it to prevent rusting. 

Method 2: Using White Vinegar

Another effective method for cleaning carbon steel knives is using white vinegar. This readily available ingredient, found in most grocery stores or even your own pantry, is a natural alternative to off-the-shelf cleaners. 

A key reason to choose white vinegar over other types of vinegar is its high concentration of acetic acid, which makes it particularly effective at removing rust from carbon steel knives. White vinegar is also the only type of vinegar that will not cause any discoloration to the knife. Now, let’s dive into the step-by-step cleaning instructions.

Cleaning Instructions:

1. Fill a container with white vinegar and submerge the carbon steel knife in it. 
2. Allow the knife to soak in the vinegar overnight (or at least 6 to 8 hours). 
3. Then, remove the knife from the solution and scrub the blades with a brush.
4. If the rust persists, soak it in a new white vinegar solution for another night. Brush it again the next day.
5. Once cleaned, wash it with soap and water and wipe it dry before properly storing it.  

Method 3: Using Baking Soda

You can also opt for other natural alternatives to cleaning carbon steel knives. One of these ingredients is baking soda. However, since you will need to mix it with water to create a paste, it’s important to be extra careful to avoid further rusting as water can promote oxidization. Baking soda can help remove rust from carbon steel knives by acting as a mild abrasive.

This helps to lift rust, which can be scrubbed away with steel wool or wool pads. To effectively clean your knife, remember not to leave the paste on for more than 15 minutes, as prolonged exposure could potentially harm the material. Here’s how you can safely use baking soda to remove rust stains from your carbon steel knives. 

Cleaning Instructions:

1. Mix a generous amount of baking soda with 1 to 2 teaspoons of water until a paste is formed.
2. Apply the paste onto one side of the knife, focusing on the rusted areas. 
3. Let it sit for about 5 minutes for mild rust and up to 15 minutes for more serious rust stains. 
4. Then, scrub the blade with steel wool to remove the rust and wipe the excess away when done. If you’re dealing with an expensive knife, you can use scrunched-up aluminum foil instead, although this may require more elbow grease.
5. Now, repeat on the other side and wipe the knife dry. 

Method 4: Using Lemon & Salt

Another natural and chemical-free solution to remove tougher rust stains is lemon and salt. The citric acid present in lemon works wonders in dissolving the rust, making it easier to eliminate. On the other hand, salt acts as a gentle abrasive, ensuring that every bit of rust is thoroughly removed from your knife. Here’s how to use these two ingredients appropriately to clean carbon steel knives effectively.

Cleaning Instructions:

1. Apply some salt onto the blades and squeeze some lemon juice on top of the salt.
2. Let it sit for about 2 to 3 hours in a dry and cool area.
3. Scrub the blade with a wire brush in a circular motion to remove the layer of rust.
4. Wash the knife with clean water only and wipe it dry completely. 

Best Practices For Maintaining Carbon Steel Knives

Proper maintenance can significantly extend the lifespan of these knives, allowing them to slice through produce and for decades effortlessly. With that in mind, mentioned below are a few ways to keep your carbon steel knives well-maintained.

• Oil the Blade: Applying a thin layer of mineral oil helps create a protective barrier against moisture and prevents rust formation. Some excellent oil options include food-grade mineral, camellia, or coconut oil. By incorporating this step into your maintenance routine, you can significantly reduce the risk of rust and keep your knives in top condition.

• Build Patina: Alongside rust, patina is also known to form on carbon steel knives. However, unlike rust, patina helps to enhance the knife’s performance and durability so you’ll want to encourage patina growth. There are several ways to achieve this, such as cutting acidic fruits or exposing the knife to food with high iron content.

• Avoid Knife Blocks: It is crucial to avoid storing carbon steel knives in knife blocks, as water buildup in these blocks can lead to rust formation. Instead, consider using a knife rack or magnetic strip to keep the blades dry and well-ventilated.

• Sharpen Your Knives By Hand: Carbon steel knives are particularly easy to sharpen by hand and doing so is highly recommended to maintain a sharp edge. All you need are sharpening stones or honing rods. Then, glide the blade across at an angle with consistent pressure and controlled movements.

Frequently Asked Questions

Below, we address some of the most frequently asked questions about cleaning carbon steel knives that were sent in by our readers. 

What’s the Difference Between Cleaning Carbon Steel Knives & Stainless Steel Knives?

When it comes to the difference between cleaning carbon steel and stainless steel knives, it’s important to understand their composition. Carbon steel is primarily made of carbon and iron, while stainless steel contains carbon, iron, and chromium. 

The chromium in the stainless steel makes it less prone to rusting compared to carbon steel. This means that if you have carbon steel knives, it’s best to avoid putting them in the dishwasher as they are more susceptible to oxidation that happens from moisture. 

However, carbon steel knives have an advantage when it comes to sharpness. They can be sharpened to a finer edge and maintain that sharpness longer than stainless steel knives, which is why they are preferred by many professional chefs and cooking enthusiasts.

How to Prevent Carbon Steel Knives from Rusting So Easily

It’s important to take proper care and follow a few guidelines to prevent carbon steel knives from rusting easily. Firstly, make sure to dry the knife thoroughly after each use. Any moisture left on the blade can lead to rust formation. 

Next, avoid soaking the knife in water for extended periods, as this can accelerate the oxidization process. Instead, quickly rinse the knife under running water and promptly wipe it dry. Another tip is to apply a thin layer of oil on the blade to create a barrier against moisture and prevent rusting. 

How to Identify Patina and Rust On Carbon Steel Knives

Patina is a protective layer that forms naturally on the surface of carbon steel knives over time and helps prevent corrosion. On the other hand, rust forms when iron present in the carbon is exposed to oxygen and moisture over time, which can ultimately damage your knife in the long run. It’s not uncommon to mistake patina for rust. 

In the image above, you’ll be able to see a carbon steel knife with a patina. It’s important to note that if you happen to come across rust on your knives, it is crucial to remove these stains promptly using the appropriate methods mentioned earlier.

How to Store Carbon Steel Knives Properly

To ensure rust doesn’t build up on your carbon steel knives, you’ll want to store them the right way. It’s important to know firstly, that you should always avoid storing your knives in a sheath or while they’re wet. 

Instead, dry them completely and oil them to create a barrier that prevents moisture from penetrating through. Then, store your knives in a dedicated drawer away from other kitchen utensils. This prevents any potential damage or scratches that can occur from contact with other tools or utensils. 

For added protection, you can fill the drawer with desiccants, such as silica gel packets. Silica gel acts as a moisture absorber, effectively preventing any moisture buildup.