Whether you have accidentally left your knife out in the rain, soaking in water somewhere or found it in one of your old toolboxes which you haven't opened for a while, chances are you have encountered a nasty surprise with rust on your knives.
Back in the old day, rust on a knife was sometimes considered a sign of a knife's quality - that it had survived long enough to warrant the eventual sign of rust. But a rusted knife is not just ugly, but also dangerous and useless.
Before we jump in, why do kitchen knives rust in the first place?
What is Rust?
Rust is another name for the compound called iron oxide ie. the red/orange flaky type substance that you see growing on metal. Iron oxide takes place when iron and oxygen react to moisture. And it doesn't necessarily even have to be water, if there is moisture in the air it can still make your kitchen knives rust.
Iron is the secret ingredient of the steel found in the blade of your kitchen knives. So when the iron in your knives is exposed to oxygen and moisture, you have a recipe for rust.
But how about stainless steel blades? Stainless steel is more stain-resistant, not stain-proof. It still has at least 10.5% chromium so it is still considered steel. It's best to think of stainless steel as having an extra protective layer which allows them to be 'stain-less' and not 'stain-free'.
How to Remove Rust from Your Knife
Now that we know exactly what rust is and how it comes about, it's time to delve into the different methods to remove this funky substance and get your knives back to pristine condition.
You may use any of these methods repeatedly in conjunction with one another for blades with a lot of rust. Just make sure to resharpen your kitchen knife afterward to ensure a sharp and safe blade.
#1 Baking Soda
Baking soda works great on knives with light rust stains or on items made out of thin metal.
Make sure to wipe down and clean your kitchen knife properly first so no dirt interferes in the rust removal process. Opt for a cleaning solution and wipe down with a cloth when removing dirt - avoid water as moisture was the agent that caused your blade to rust in the first place.
Mix water and baking soda so that it creates a thick paste, and then spread it over the metal making sure all rusted spots are completely covered. Let the paste sit for approximately an hour.
Then using a toothbrush, scour away at the rusted spots. For extremely rusted knives, use steel wool or a slightly abrasive sponge, but take note that too much pressure can damage your knives.
Then remove the paste with water and dry thoroughly with a cloth. To give your kitchen knife a protective boost from rust and keep it lubricated, apply some mineral oil such as camellia oil which should do the trick.
#2 Vinegar Method
White vinegar contains a substance called acetic acid which attacks rust. Avoid using other types of vinegar as they may leave stains.
Soak your knife in white vinegar for roughly five minutes. Any longer and you risk damaging your knives.
After the five minutes is up, if there is still some rust remaining then progressing to the baking soda method should remove any last specks of rust. And then we recommend lubricating your blade with camellia oil to make it more rust-proof in the future.
Otherwise, just wash off the vinegar with water and wipe and dry with a cloth.
#3 Lemon and Salt
Combining the acidity or lemons with the abrasiveness of salt helps tackle small rust spots.
Cover the rusted areas on your blade with salt, and squeeze lemon juice on top. Let it sit for about two hours.
Then scrub the areas with lemon rind. If you need something more abrasive, use steel wool or a slightly abrasive wire brush to scour the areas.
Rinse off the blade with water and dry with a cloth.
#4 Potato Method
Potatoes are surprisingly effective at removing rust due to their oxalic acid content.
Simply stick your knife into a potato and let it sit for a few hours. After you remove it, wipe down the blade with oil and the rust should be gone.
#5 Onion Method
Another food that is great at removing rust from blades naturally. Just by sliding the blade back and forth when cutting onions will do the trick and the rust will come off by itself.
The sulfenic acid in onions which are notorious for breaking down adults into puddles of tears when slicing an onion are also the key ingredient in getting your kitchen knives cleaned.
When All Else Fails, Grab a New Knife!
If your knife is beyond repair, or if it's going to be too much work trying to remove the rust than you're willing to put in, it's OK to move on.
We stock premium quality knives from the world's best brands, and they all come with manufacturer warranty and guarantee to ensure your knives last you for many years to come.
Also Read: Exploring the Shun Kanso Series