5 DIY Ways To Do Knife Rust Removal

Written by: Forged Blade

January 8, 2025

Time to read 7 min

Knife rust removal is a pain, but it's one of those things we all have to deal with at one point or another.

As a knife enthusiasts - who have been both buying and forging knives for years - we know a thing or two about collecting high-quality blades that are designed to last a lifetime. But, even though we go for quality, our knives still need occasional rust removal. It's just part of the game.

Even the best knife will start rusting if it's not taken care of properly. So, let's learn how to prevent rusting in the first place and clean a rusty blade if it happens.

Need a blade to practice on? Shop our knife collection.

What is Rust? Why Do Knives Rust? How To Remove Rust From Kitchen Knives 1. How To Remove Rust From A Knife With White Vinegar
2. How To Remove Rust From A Knife With Baking Soda 3. How To Remove Rust From A Knife With A Potato 4. How To Remove Rust From A Knife With An Onion 5. How To Remove Rust From A Knife With Toothpaste
When to Get A New Knife Summary Frequently Asked Questions Related Readings

What is Rust?

Rust is a chemical reaction that occurs when iron combines with water and oxygen. Rust can occur on any metal, but it's more common to see in areas where there's an abundance of moisture in the air, such as near the ocean or in humid regions.

Why Do Knives Rust?

The majority of knives are made from some kind of steel which is a metal that is susceptible to rusting. Several factors can increase the likelihood that your knife will rust:

The type of metal used in the knife. Stainless steel has higher corrosion resistance than carbon steel, but both are prone to rusting if they're damaged or exposed to moisture. Luckily steel and stainless steel rust removal is possible!
The environment in which your knives are stored. If you keep them in a damp or humid place, they'll be more likely to develop rust spots. If you store them in a dry area but expose them to water without properly drying, this can also lead to corrosion because of residual moisture that can get trapped inside the knife as well as any minerals from water that have been absorbed into its surface.
How often you clean your knives after use (or don't). Leaving food on an uncleaned blade overnight is one thing; leaving it for weeks at a time is another!

How To Remove Rust From Kitchen Knives

The best way to prevent corrosion on your kitchen tools is through regular cleaning with soap and water—or better yet, mineral oil—and proper storage away from corrosive elements like heaters and sinks ledges where excess moisture may collect during cooking activities."

However, if your blades already developed some rust spots, you can try the following 5 DIY methods to help remove rust from knives.

1. How To Remove Rust From A Knife With White Vinegar

White vinegar rust removal is an easy, inexpensive DIY way to remove rust from your kitchen knives or blades.

Here's how:

Dip the knife in white vinegar.
If it's cooking-grade stainless steel, let it sit for 10 minutes. For all other grades of steel, let it sit for an hour.
Note: You can also use a rust remover like CLR to speed up this process, but be sure not to leave your knife in too long or you'll damage its finish.
Rinse the knife off with warm water and dry it with a towel before handling again.
Repeat as necessary until no more rust remains on the blade; if there's still some left after two rounds of this process read on.

2. How To Remove Rust From A Knife With Baking Soda

Baking soda is an excellent tool for DIY rust removal. It's safe and easy to use, and it won't damage the surface of your knife. Here's how:

Mix 2 tablespoons of baking soda with 1 tablespoon of water; depending on the size of your knife and the amount of rust, you may need to add more water or baking soda.
Dip a soft cloth in this solution and rub it onto all areas where rust appears to be present, paying close attention to tough spots like serrated edges and rusted screws.
Apply some elbow grease by rubbing vigorously for 10-15 seconds; then rinse under warm water until all traces are gone!
Dry thoroughly before storing again so as not to leave any moisture behind that could cause new corrosion issues later on down the line (which is bad news bears).

3. How To Remove Rust From A Knife With A Potato

You can remove rust with a potato. Shocking, but yes, it works! Potatoes contain Oxalic acid which is a powerful acid rust remover as it reacts to destabilize rust particles on the blade. To remove rust from a knife with a potato follow the steps below:

Boil a potato in water for about 15 minutes
Peel the potato and cut it in half
Rub the cut surface of each half of your peeled, boiled potato over any rusty area on your knife until all visible rust is gone
Rinse off all remnants of the potato pieces and dried peel from your blade/tool and repeat until no more rust remains

4. How To Remove Rust From A Knife With An Onion

While a little bit unconventional, onions can be effectively used for DYI rust removal from a knife. Onion contains Suplhenic acid and reacts with rust when rubbed against it. Here's how:

Peel and slice the onion. Slice the onion with a sharp knife (ideally not the rusted knife), remembering to cut away from yourself.
Put the onion slices on the blade of your knife. The best place is near where you hold it when using it, but don’t put them too close to where they could get in your way!
Place on a flat surface and leave for 24 hours before washing off with water and drying off with a paper towel or cloth (not used towels!)

5. How To Remove Rust From A Knife With Toothpaste

Another simple and effective DIY method to remove rust from knives is by using toothpaste. Here's how:

Use a soft-bristled toothbrush (or other similarly soft brush) to scrub the affected areas clean.
Dip a cloth into warm water and wring out as much excess moisture as possible before wiping the blade down with it until it's dry again.
Use some of your favorite toothpaste (white or gel—it won't matter) and apply it directly onto the blade; then gently scrub away until all traces of rust have been removed from its surface!

When to Get A New Knife

"If you have tried all of the above methods and still can't remove rust from your knife, then it's probably time to get yourself a new knife."

The truth is that sometimes the rust on the knife will be far too advanced to remove without some extremely heavy-duty solutions.

A good chef’s knife should last you many years, so investing in one that will hold up is important. If you find yourself having to replace your knives often because of rust or other issues, then something is wrong with the quality of what you're buying and you should consider getting something better ASAP. Some sneaky manufacturers design their knives with poor-quality steel in order for them to rust quicker and force you to replace your knives often.

At The Forged Blade we strive to design beautiful high-quality knives that are meant to be used for a lifetime. This is why our razor-sharp knives come with a lifetime guarantee and are extremely rust resistant. If you are looking to upgrade your knife, take a look at some of our best selling collections above or shop all of Forged Blade's products.

P.S. Our 50% OFF SALE is ending soon. Order Now to secure yours.

Discover our knives

Summary

Even with the best quality knives, rust is going to happen.

Knives rust because of the materials they're made of, the environment they're stored in, and how they're maintained.

You can try to remove rust with vinegar, baking soda, a potato, an onion, or toothpaste.

If none of these methods work, it's time to get a new knife.

Frequently Asked Questions

Why are my knives rusting so fast?

Knives made with steel are prone to rusting if not properly maintained. Moisture exposure, improper cleaning and storage conditions are the main reasons knives rust. Check out our knife care and maintenance guide for tips on how to avoid rust on your expensive blades.

Is it ok to cook with a rusty knife?

Cooking with a rusty knife is generally unsafe. Rust can flake off and contaminate food, potentially causing harm if ingested in large amounts over time. While small amounts of rust might not cause immediate health issues, frequent exposure could lead to issues. If you spot rust on you knife, follow the advice in this article to remove it.

What to do if you get cut by a rusted knife?

If you get cut by a rusty knife, immediately clean the wound with soap and water, apply antiseptic, and monitor for signs of infection like redness, swelling, or pus. If the knife was heavily rusted and you haven’t had a tetanus booster in the last 5–10 years, consult a doctor about getting one. Seek medical attention if the wound is deep, won’t stop bleeding, or shows signs of infection.