The Cutting Edge

The official blog of Knife Depot

How to remove rust from the blade of your knife

Knife with rustWhether you’ve found an old knife in one of your old toolboxes or accidentally left your favorite knife outside in the rain, chances are you have encountered a nasty case of rust. Many old timers considered rust the sign of a knife’s quality, but a rusted knife is also dangerous, useless and downright ugly.

Over the years, people have come up with a wide variety of ways to remove rust from the blade of a knife. Many of these might do the trick for you, but heavier rust might require a few methods.

1) The first thing you want to do is thoroughly clean the blade of your knife because dirt can interfere with the removal of rust. Don’t use water because that’s what mostly made your knife rust. Instead, use some sort of cleaning solution and wipe it down with a cloth.

2) Next, apply another coat of rust remover for knives. Soak a rag in oil and cover the knife with it for a few hours to let the solution get into the rust. You can use nearly any type of oil, including WD-40, kerosene, Vaseline, Autosol and even white vinegar.

3) Remove the blade from the rag and scrub off any rust. Most rust removers come with an abrasive cloth, but you can also use steel wool to get it off.

4) Wipe off any excess dirt and oil with a cloth and your blade should look good as new. If not, repeat the above steps with a different cleaning solution or try one of the alternative methods below.

Alternative Methods

-Certain foods also act as a good sources for rust removal. The potato is actually remarkably effective food for removing rust because of its oxalic acid. Simply stick your knife into the potato for a few hours. After you remove it, wipe the blade with oil and the rust should be gone.

-Onions are another food that helps get rid of rust naturally. If you saw back and forth into an onion, the rust will begin to come off by itself. The sulphenic acids in onions are they key ingredients in getting your blade cleaned.

-Another more natural way many people suggest is to plunge your rust-c0vered knife into rich soil about two dozen times and then wipe it clean.


  1. baking soda also works! 😀

  2. Tabasco sauce works wonders as well.

  3. If it’s really bad, I spray with WD40 and let sit as mentioned. Then scrub with hot water and an SOS pad. Scotch-Brite pad next and finish off with Autosol polish.

  4. Can you use dish soap to wipe is down?

  5. I used the potato idea. Much to my surprise, it really worked. Even after 20 minutes I noticed a major difference. Thx guys for the science experiment. I was totally amazed.

    • Tim

      July 1, 2016 at 3:34 pm

      Glad it worked for you. It’s crazy to think how something so simple and mundane can work wonders on a rusty blade.

  6. I tried the potato idea, although it did get rid of some of the rust, it left a stain of some kind on my knife that I can’t seem to get rid off..

    • Tim

      September 18, 2016 at 7:54 pm

      If it’s a carbon steel, you probably just forced a patina. This is actually a way to prevent rust in the future, but if you don’t like it you can polish it out.

      • Is that patina black my blade turned that color after I used vinegar smells like old metal don’t wanna cut food anymore cause of it

  7. Would any of these tricks work on a X-acto knife

    • Nikolai Ushakov

      July 22, 2017 at 9:18 am

      Yes, most of these will work on an x-acto knife. Although I usually get away just using some 00 steel wool then sharpen it it after.

  8. I found one of my dads old knives in a shed and I am letting it sit in a gun oil soaked sock. Hope this works

  9. Sustain the incredible work !! Lovin’ it!|

  10. Hmmm… just need to find a potato big enough for my Cold Steel XL Espada lol.

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