Your knives do a lot of the most important and heaviest work in your kitchen.
Your knives also take a lot of punishment in the process, from cutting through tough vegetables like squash to cutting through joints and even bone.
It’s no wonder that your knives need a little TLC from time to time. Rust is a sure sign that your knives could use some attention.
Fortunately, there are lots of things you can do to remove the rust on your knives.
I’ll also go over some preventive maintenance that will help keep your knives rust-free longer, and some common risk factors that can make your knives rust sooner.
These tips apply to Western and Eastern knives, though you may have to be more careful with knives made from Damascus steel for reasons I’ll explain later. For now, just remember that patterned and painted steel can be much harder to de-rust.
What You’ll Learn in this Guide:
- Several common methods for removing rust from kitchen knives
- Rust preventive maintenance
- Which types of steel are most likely to rust (and what to do about it)
- And Much More!
What's in this Guide?
What Are The Benefits of Learning to Remove Rust from your Knives?
The main benefit of removing the rust from your knives is that you get to keep them longer. Rust makes your knives more delicate since oxidized steel isn’t as strong or durable as non-oxidized steel.
Rust can also eat away at your knife’s blade, leaving it dull and sometimes even chipped.
Over time rust can put a knife completely out of commission.
Some metals are more prone to getting rusty than others. High quality stainless is rust resistant. High-carbon steel, on the other hand, is prone to rusting. There are benefits to both types of metal, but if you own a high-carbon steel knife you need to know how to remove the rust.
Often old rusted knives can be revitalized with relatively little effort. Just remove the rust and give the knife a quick sharpen and you should be good to go.
This video covers a lot more than just removing some rust. Hopefully you won’t have to re-finish the blade or replace the handle on any of your knives. I still like it though because it really shows that you can successfully restore a good knife in almost any condition with a little dedication and know-how.
What You Need To Know About Removing Rust from Your Knives
The first thing you need to know is that once a knife has rusted it’s more likely to rust again.
That’s because rust is just oxidation of the metal. When you remove the oxidized metal you’re left with a surface that isn’t quite as smooth as it was. The scratches or pitting on your knife can hold water. Water on your knives is a recipe for rust.
Fortunately, you can take some steps to help prevent rusting. Oiling your knives once every few months is a great first step to prevent oxidization. Mineral oil is a good, food-safe, option for most knives.
You should also know that you may need to use different techniques to remove the rust from different knives. The thickness of the metal and how rusted your knife is should dictate which method you use.
It’s more difficult to remove rust from patterned blades like Damascus steel, and may remove designs from other kinds of blade as well. If your knife has any decorative elements on the side, consider taking it to a professional to remove rust instead of doing it yourself.
Also, be prepared to put in a little elbow grease. Removing rust isn’t difficult but it does take some time and patience. Having the right tools will make it easier.
How To Remove Rust From Your Knives
Since there are so many different methods to remove rust from your knives, I’m going to tackle this a little differently. If you’ve read some of my other guides you probably know that I usually give you a supply list before breaking down the steps you should use.
That doesn’t make a ton of sense here. Instead, I’ll give you a supply list for each method instead of one big supply list. That way you can immediately tell what you need for your chosen method and won’t waste time and money getting tools you don’t need.
Method 1: Baking Soda
The baking soda method is a good option if you’re working with a thin knife blade. It’s slightly gentler than some of the other methods on this list, and won’t hurt the structure of your knife at all.
Baking soda is also a good solution for thicker knives with very little rusting.
Supplies You’ll Need
- Baking soda (a tablespoon or two is more than enough)
- A small bowl
- A toothbrush or other gentle abrasive tool
Step 1: Mix Your Baking Soda and Water
Before you start, go ahead and grab all of the knives that need rust treatment. If you’re going to work on one knife, why not clean them all?
Once you have all of your knives, mix your baking soda and water together. You’re looking for a thick paste, roughly the consistency of toothpaste. It doesn’t take much water.
Thankfully, you can add a little more baking soda if your first paste is too thin.
Step 2: Cover the Rust with Baking Soda Paste
Spread the paste over each of your knives. It’s important that the paste cover all of the rust completely but you don’t have to completely cover the knife.
Leave the knives to rest for about an hour.
Step 3: Scrub off the Rust and Paste
Use your toothbrush to scrub off the rust. Don’t worry about removing the baking soda paste before you get started, the baking soda itself acts as a mild abrasive to help you remove the rust.
If your toothbrush doesn’t remove all of the rust you can go ahead and use some steel wool or another stiffer abrasive to help. Start with the toothbrush though. Steel wool and other harsh abrasives are more likely to leave small scratches in your knives.
Those small scratches are more likely to rust later on.
After you’ve removed all of the rust, wash your knives with soap and water and dry them as normal.
Method 2: Vinegar Soak
Soaking your knives in vinegar is a good option for knives with thicker metal or a lot of rust.
Alternatively you can use pure citric acid from the store the same way.
Just be careful, you don’t want to mix citric acid too strong or it might damage your knives.
- Distilled white vinegar
- A bowl large enough to hold your longest knives
- A toothbrush, steel wool, or other abrasive
Step 1: Soak Your Knives Overnight
Just like before, go ahead and gather all of the knives that need rust removed. It’s easier to do them all at once rather than one after another.
Pour your distilled white vinegar into your bowl. I like to buy white vinegar by the gallon because it’s cheap and useful for cleaning and laundry as well as in the kitchen.
Place your knives in the bowl. If your knives have wooden handles, keep the handle out of the vinegar. Over time the vinegar can harm the wood, and you should never let wooden handles soak in any liquid.
Make sure all the rust is completely submerged or this method won’t work.
Leave your knives submerged overnight. If you can’t scrub them right away in the morning, leave them in the vinegar until you can.
Step 2: Scrub Your Knives
Take your toothbrush or other abrasive and scrub the knives. You can dip them back in the vinegar as you work to rinse off any rust flakes that accumulate while you’re scrubbing.
The rust should be much softer and easier to remove at this point, so it shouldn’t take too much work.
Step 3: Wash, Rinse, and Dry
After you’re done, make sure you wash your knives with soap and water as normal. White vinegar is food safe but it doesn’t taste good like other vinegar does. You don’t want to leave any on your knives where it can get on your food later.
Make sure you dry your knives thoroughly after removing rust. You don’t want to set up the conditions for more rust right away.
Method 3: Potato Rust Removal
Yes, a potato is the main tool for this method. Potatoes are effective at removing rust because they have a relatively high concentration of oxalic acid, which is also found in spinach and lots of other foods.
Oxalic acid is effective for lifting and removing rust.
The potato you use won’t be edible after you’re done. Don’t use a potato you need for a recipe.
- One large potato, halved
- Dish Soap
- Baking Soda or Salt
Step 1: Prepare Your Potato
The first thing you’ll need to do is get your potato ready to start. Just like the previous methods, grab all of your rusty knives first, then slice your potato in half.
Pour a small amount of dish soap onto the potato slice. The soap will make it easier to scrub and also helps clean your knives.
Last, you’ll want to sprinkle a small amount of salt or baking soda over the soap. Both ingredients act as mild abrasives and help make the whole process faster.
Step 2: Scrub
Now that your potato is ready, it’s time to get scrubbing. It may take a minute or two before you start to see rust coming off of your knives, but the rust will come off faster the longer you work. That’s the oxalic acid working.
Scrub anywhere there is rust until the knife is clean. If your soap is foaming too much for you to see, rinse your knife and dry it before you start again.
Depending on how much rust you have, and how many knives you’re treating, you may need to add more dish soap, baking soda, and salt to the potato.
If your potato starts to fall apart, switch to the other half.
Step 3: Wash and Dry
Once you’re finished, toss your potato and wash and dry all of your knives. Make sure each knife is completely dry before putting it back in storage.
Method 4: Metal Glo Polishing Paste
For the last method I wanted to look at something a little less DIY.
Metal Glo Polishing paste is designed for knives and other kitchen metals as well as jewelry and fine metal.
If you choose to go with this method just make sure you wash your knives very thoroughly afterward to make sure you’ve removed all of the polishing paste.
- Metal Glo Polishing Paste
- Polishing cloth
Metal Glo Polishing paste will provide step instructions for you, depending on what kind of metal you’re using. While I would normally give you a step-by-step process, it’s best to follow their instructions for the type of metal you need to polish.
I do want to note that one advantage of this polish is that it also protects your knives. None of the other methods I’ve mentioned protect from future damage unless you also oil your knives afterward.
My Final Thoughts on Removing Rust from Your Knives
Removing the rust from your knives might sound like an intimidating task at first. Thankfully, this critical process is actually very simple. Maintaining your knives so that they don’t rust, using polish or oils, is also important, but knowing that you can restore your knives after they rust can be a huge relief.
Now you know exactly what to do if you inherit old rusted knives, or if you discover that your prized kitchen knife collection rusted during the move.
Remember that you should almost always sharpen your knives after removing rust.