How to Remove Rust from Knives

Even with the best care, stainless steel knives—and especially carbon steel knives—can develop surface rust or corrosion over time. Whether it’s a trusty steak knife, a favorite pocket knife, or a high-end chef’s knife, knowing how to get rust off knives can help you preserve performance and longevity.

In this guide, we’ll walk you through five easy ways to remove rust from knives, including natural solutions like baking soda and lemon, plus essential tips on how to keep your blades rust-free going forward.

What Causes Knives to Rust?

Rust forms when iron in the steel reacts with oxygen and moisture—a natural process called oxidation. While water alone can start it, acidic foods like tomatoes, citrus and vinegar speed things up significantly. If a knife isn’t cleaned thoroughly or is left damp, these elements can linger on the blade and lead to corrosion. Over time, this reaction creates rust, or iron oxide, a sign your knife needs a little extra care.

Can Rusty Knives Be Saved?

Absolutely. Rust doesn’t have to mean the end for your knife. Most rust sits on the surface and comes off with minimal effort. Light spots or heavy buildup—either way, simple household methods can often restore your blade. A little care and the right technique can bring even the dullest knife back to life.

5 Ways to Get Rust Off Your Knives

Save your favorite blade from rust—here are five effective, kitchen-safe methods to get rust off your knives and restore their shine.

1. Remove Rust with Baking Soda Paste

Baking soda, (sodium bicarbonate) is a common household ingredient that is useful for removing rust from a kitchen knife. Not only is the texture slightly abrasive, but its mild alkalinity helps lift oxidation without damaging the blade. The baking soda method is ideal for cleaning up light rust on both stainless and carbon steel blades.

Steps:

1. Mix baking soda with a small amount of water to create a thick paste.

2. Apply the paste to the rusted areas of the knife.

3. Let it sit for 1–2 hours.

4. Use a soft cloth to massage the rust spots. If that doesn’t work you can gently scrub with a scouring pad, toothbrush or soft sponge. Avoid steel wool, which may scratch the blade.

5. Rinse with warm water and a bit of dish soap 

6. Dry the knife thoroughly with a soft towel (don’t air-dry) and store in a dry place.

2. Use a Whetstone Rust Eraser

Rust erasers are specialized tools made from rubber mixed with abrasive particles like silicon carbide. They’re easy to use, minimize damage to the blade, and work well for persistent rust spots. They're especially useful for carbon steel knives with persistent stains.

Steps:

1. Soak the rust eraser in water for 5 minutes.

2. Gently rub the eraser over the affected areas, moving with the grain of the steel to remove rust stains.

3. Re-wet the eraser during use if it starts to dry out.

4. Once rust is removed, rinse the knife, wash it with dish soap, and dry it completely.

Browse sharpening accessories, including rust erasers and sharpening stones, to maintain your blades over time.

3. Scrub with Lemon (citric acid) and Salt

The natural citric acid in lemon juice helps dissolve rust, while coarse salt acts as a gentle abrasive to lift it away. This method is great for light surface rust and requires no special tools, instead using common household items you most likely already have lying around.

Steps:

1. Sprinkle coarse salt over the rusted parts of the knife.

2. Squeeze fresh lemon juice over the salt until it’s saturated.

3. Let it sit for 15–30 minutes. For carbon steel knives, avoid leaving it on too long, as acids can cause further staining.

4. Scrub gently with a soft sponge or brush, following the grain of the steel.

5. Rinse thoroughly, wash with dish soap, and dry immediately. Store in a dry environment.

Tip: You can also mix lemon juice with baking soda for a fizzy, slightly less abrasive cleaning paste.

4. Soak in White Vinegar

White vinegar contains acetic acid, which reacts with iron oxide and helps break down rust buildup. It’s a simple and affordable method for more stubborn rust but timing is key to avoid damaging the blade.

Steps:

1. Submerge the rusted section of the blade in plain white vinegar (5% acidity is standard).

2. Let it soak for 30 minutes to 2 hours, depending on the severity of the rust.

3. Remove and gently scrub with a brush or non-metallic scouring pad.

4. Rinse thoroughly with soap and water.

5. Dry the knife completely to prevent further corrosion.

Tip: Avoid soaking too long, especially with carbon steel blades. Extended exposure can etch the surface and dull the finish.

5. The Potato Method

Potatoes naturally contain oxalic acid, a mild organic compound that can dissolve light rust without harsh chemicals. It’s a surprisingly effective and food-safe method—especially for smaller knives or delicate finishes.

Steps:

1. Slice a raw potato in half and dip the cut side in baking soda or coarse salt.

2. Rub the potato directly onto the rusted area using circular motions.

3. Alternatively, insert the knife blade into a whole potato and let it sit for 1–3 hours.

4. Remove the knife, rinse thoroughly with water, wash with dish soap, and dry completely.

Avoid These Chemicals

While products like WD-40 or harsh degreasers can clean rust on tools, they’re not safe for kitchen knives. These chemicals are not food-safe and can leave behind residues that are toxic if ingested—even after rinsing. Using them on cooking knives creates unnecessary health risks and may even damage the finish or compromise the steel. 

Stick to natural or food-safe solutions for any utensil that touches what you eat. When in doubt, ask yourself: Would I feel okay if this cleaner was on my food? If not, don’t use it on your knife.

How to Prevent Rust on Knives

Preventing rust is all about consistent care and smart storage. A few simple habits can keep your blades sharp, clean, and corrosion-free:

• Wash and dry immediately after each use. Never leave knives soaking or air-drying.

• Never use dishwashers. The high heat, prolonged moisture and harsh detergents can damage both the steel and the handle.

• Store in a dry place. Knife blocks, magnetic strips, or sheaths are a great option. Avoid tossing them in a drawer where moisture can build up.

• Maintain your edge regularly. Use sharpening stones regularly to keep blades in top shape.

• Carbon steel knife care. Apply a light coat of food-safe oil after cleaning to protect against oxidation and moisture.

Explore our guide on how to avoid ruining a Japanese kitchen knife for more expert knife care tips.

Bring Your Cutlery Back to Life or Upgrade with Chubo Knives

Whether you’re restoring a rusted blade or looking to prevent future rust, these five methods offer simple, effective solutions for every type of knife. From baking soda paste to the surprisingly effective potato trick, a little elbow grease can keep your knives sharp, clean, and rust-free.

And if it’s time to retire a damaged knife, explore our premium knife collection featuring hand-forged Japanese craftsmanship.

Want to know when it’s time to replace your blade? Read our guide on signs it’s time to replace your chef’s knife.