Every camper, homesteader and prepper likely has that one, trusted tool that they carry with them absolutely everywhere they go. They’re cherished, reliable pocket knife.
From camping expeditions to training days or just running errands around town, we call on our pocket knives for all sorts of tasks, from the mundane slicing of tape to the heavy-duty business of slashing through stuck webbing or vines.
We ask an awful lot from our knives, and if you use your knife often, or just carry it often, it is probably only a matter of time before your favorite companion picks up a little bit of rust.
Now, for the collector or the knife hoarder, rust formation will very likely result in red-faced fits of rage and copious tears but for us, this is just one more thing we’ve got to take care of. We sharpen our own knives, and we need to remove rust from them, too.
But if you have never done it before, rust removal might seem like a bit of a puzzle. How are you supposed to get this hard stuff off the knife without hurting the steel that is host to it?
I will show you how to do that and more, with eight surefire, tried and tested methods for cleaning up your pocket knife.
Table of Contents
Get That Rust Off!
Okay, time to get down to business because, the longer you let rust remain on your knife, the worse the damage will be. It doesn’t matter how that rust showed up on your knife.
Maybe you carried it on some seriously hard-working days where you sweated right through your clothes, drenching it with salty perspiration.
Maybe it rode with you on a trip down to the beach. Maybe it got completely soaked during a river crossing. Maybe your knife is just made of comparatively delicate carbon steel and you didn’t oil it after you were done handling it.
All you need to know is the rust shouldn’t be there and we need to gather our tools to ensure its elimination.
Now, I will give you a short list of items to gather here in just a minute, but I want to impress upon every reader, especially those who are not knife aficionados that you should not attempt to remove rust from a knife, or use a knife, that is showing severe rusting or pitting on the blade, locking surfaces or other critical components.
Rust is corrosion, and where rust forms the degradation and eventual disintegration of metal follows.
If you have any doubts about the structural integrity or safety of your knife, consult a professional bladesmith or the manufacturer for guidance. A mishap with any knife can result in severe lacerating or penetrating injuries. You have been warned!
Tools of the Trade
Okay, disclaimer over. Time to go shopping. Luckily you won’t have to go far because you probably already have most of these supplies in your very own home.
Some of the specialty chemicals and items you might need will be mentioned in their own list of procedures below.
Here’s what you’ll need in any case:
Steel wool is typically used for serious rust removal, but for badly neglected blades this is just the ticket. You’ll want to pick up 000 and 0000 grade steel wool. Be warned, steel wool will easily leave swirly cobweb marks on nearly any finish.
This looks like a toothbrush but one with bristles made from copper, not plastic. Definitely don’t use this on your teeth.
Note; make sure you are getting a genuine copper brush, not one made from bronze or phosphor bronze. They look alike, but bronze is far more aggressive than copper, too aggressive for our purposes.
Coin, penny, pre-1981
This isn’t a joke. You need an actual copper penny. If you find one dated from the year 1981 or before you’ll know it is genuine copper so long as it has that reddish color to it. We can use this as a steel safe scraper to bust off the gnarliest rust deposits.
We’ll be working with various lubricants and chemicals for the process that we don’t necessarily want lingering on our skin. Plus, particles of rust can stain like the dickens, so where are some good disposable gloves while you work.
Use a 100% natural fiber rag while you work, both to protect your work surface and to wipe off the knife as you work. Avoid synthetic fibers, because they can melt or turn to sludge when exposed to harsh rust removers.
Rust removal solution
Specialty rust removers are a dime a dozen, and you don’t need to get one that is specially formulated for knives unless you have serious doubts about the aggressiveness of the solution in question. If you don’t have any rust remover, you can use typical gun bore cleaner in a pinch.
Oil provides lubrication for the rust removal process when dealing with light rust and will treat your blade when you are done to prevent further formation or accumulation of rust. Almost anything will do here, you can even grab a little bit off your car’s dipstick in a pinch.
Vise or clamps
Sometimes you need a third hand to hold your knife while you really go to town on removing rust. A bench vise or sturdy, padded clamp can do that for you.
Eight Options for Rust Removal
Now that we have gathered our needed materials, it is time to get started. Start by protecting your work area, donning any protective gear you might need and then gathering your tools for the job.
Then, we will attack the rest using a successively more aggressive methodology in order to do the least possible harm to the metal of the knife as well as the finish.
But before we do that, look your knife over well and consider how the rust got there. Do you notice a couple of reddish fingerprints on your blade? That is probably from handling or from an errant touch with sweaty fingertips.
No disassembly required. Is the knife covered and rust from stem to stern because you dropped it in a puddle or had it in your pocket during a river crossing? You’ll probably need to take it apart and detail it.
Do what needs to be done, then try the following procedures in order. If you complete all three steps and still have issues with rust, you’ll need to leave it to the pros unless you want to risk damaging or destroying the knife.
Option #1: Treat and Wipe Down
For dealing with light deposits of rust, especially hardy steel or incidental dust rust that typically occurs from handling, this method is probably all that will be required.
At worst, you might need to soak the affected area of the knife in the rust remover for a short period of time but nothing more than that.
Do the following:
- Soak a patch or another, small rag with your rust remover solution.
- Start wiping the affected area of the knife in the direction of the grain of the steel and watch for the rust to start coming off. You should notice reddish or brownish streaks on your rag or patch.
- If that fails to budge the rust, it is time to soak the affected area. Re-soak your rag or get a new patch and place it in contact with the affected area. Follow the manufacturer’s instructions for the rust remover and don’t leave it on too long.
- Once the prescribed amount of time has passed, repeat the first two steps and see if the rust comes off.
- If the rust did come off, you are done, wipe the knife dry and then re lubricate as normal. If the rust did not come off, wipe it dry but don’t re-lubricate it and move on to the next method.
Option #2: Brush It
Assuming the first step in this process didn’t work, don’t worry. There is no need to panic and still plenty of opportunity to get the rust off your trusty pocket knife. Nonetheless it is time to bust out more substantial tools like that copper brush on your shopping list above.
However, understand going into it that despite the comparative gentleness of a copper brush compared to a bronze one and however tough you think the finish of your knife is there is a chance that you will leave cobweb marks behind.
Do the following:
- Thoroughly wet the rusty parts of the knife with your rust remover solution.
- Splash a little bit of the rust remover solution on your copper brush.
- Gently scrub the brush back and forth over the rust being cautious to move only in the direction of the grain visible in the steel.
- Check regularly as you go for removal or degradation of the rust. If no rust is coming off, start slowly increasing pressure.
- Add more rust removal solution as you need it throughout the process.
- Once you get the rust off, wipe the knife dry with a clean cloth as before and then re lubricate it. If this process still didn’t get the rust off or stubborn rust remains behind, wipe it dry but don’t re-lube it and then move to the final step.
Option #3: Scrape It
If you have made it this far you must be dealing with some fairly serious rust and our final step is similarly serious. Here we bust out the penny and the steel wool, two tools that are pretty likely to mar the finish of your knife.
Understand that if you try to do anything more than this you risk seriously damaging your knife at worst, or badly harming the finish at best.
Try the following steps before you throw in the towel:
- Thoroughly soak the affected area of the knife with your rust removal solution, and allow it to sit for the manufacturer’s prescribed time.
- After soaking is completed, use the penny and firmly try to scrape off the rust deposits in the direction of the grain, forward or backward. The penny should prove to be strong enough to cut through and crush any rust deposits, but not damage the steel of your knife. Note that the penny will leave behind copper swipe marks but they are easily enough removed.
- Once major surface deposits of rust are removed, wipe the knife clean, reapply rust remover and break out the steel wool.
- Start with 0000 steel wool. Gently swipe over remaining, fine rust moving only in the direction of the grain present in the metal. Resist the temptation to scrub in tiny circles or back and forth motions as this will leave glaringly obvious cobweb marks in your finish.
- If the 0000 steel wool did not work, wipe off, we went with rust remover and then try the same process again with the 000 wool and observe for any improvement.
- Hopefully the rest is now finally gone. If it is, wipe the knife dry with a clean cloth, re lubricate and get back in business. If, however, this fails to remove the rust you should seek professional help if you want to save the knife without risking further harm.
Option #4: Baking Soda Scrub
If you need an abrasive solution to serious rust deposits, particularly those that have pitted the knife blade somewhat, you might try to create a baking soda scrub to tackle the rust.
All you’ll need in addition to the tools listed above is a little bit of baking soda, but you can apply directly to the blade before creating a paste, or make the paste separately and then apply it.
Do the following:
- Sprinkle baking soda directly on blade of knife, followed by a few drops of water. Use a sponge, rag or paper towel to mix until thick paste forms. Alternately, mix paste separately and then spoon onto blade.
- Use a rag, sponge or paper towels to work solution into rust.
- Allow paste to sit for at least 30 minutes.
- Carefully scrub using sponge or rag. Observe for removal or degradation of rust.
- If rust isn’t coming off, slightly increase pressure.
- Continue until rust is completely removed.
- Thoroughly rinse and clean entire knife and relubricate as soon as you’re finished.
Option #5: Lemon Juice and Salt Scrub
This option probably raised a few eyebrows, for sure. Why on Earth would you want to put lemon juice, something so acidic and prone to causing rust, on the fine stainless steel or carbon steel of your knife?
That’s easy; because it can help you get light rust stains off, particularly that all over, light dusty rust that typically forms on tools that haven’t been used in a little while!
This patchy rust is easy prey for this lemon juice and salt mixture which will hit the rust with a one-two punch, breaking it down and scraping it away at the same time. Best of all, so long as you don’t leave it on there, it’s surprisingly gentle compared to some other rust removal chemicals out there.
Do the following:
- Wipe off any heavy deposits from blade of knife.
- Sprinkle lemon juice all over blade of knife.
- Apply salt. Fine salt works better than coarse salt for this purpose.
- Using rag, sponge or paper towels, carefully scrub blade of knife to remove rust.
- Observe for removal of rust. You’ll know it’s working when it starts to discolor your cloth or sponge.
- Regularly reapply lemon juice and salt to keep working the rust down.
- When it rust is removed, thoroughly rinse, dry and relubricate knife.
Option #6: Potato Method
I know we were getting into some pretty strange territory, but this is an old-timers’ trick that your great-grandfather knew. And he knew it because it works!
As it turns out, potatoes contain oxalic acid, an acid that is suitable for, you guessed it, breaking down rust. It is comparatively mild compared to some other things on this list, and in conjunction with an abrasive agent like baking soda or fine salt it can do the trick on a few modest patches of rust with minimal mess and minimal fuss.
Do the following:
- Acquire potato. Cut in half at the middle.
- Lay knife down on flat, non-marring surface. Blade should be flush with surface.
- Sprinkle fine salt or baking soda on rusty patches.
- Use potato to press down and scrub rust.
- Using cloth or paper towels, wipe off occasionally to observe for removal of rust.
- Repeat step three and four as necessary, cutting slice of potato to expose fresh surface as needed.
- When finished, thoroughly rinse knife, wipe dry and then re lubricate.
I hope you don’t need me to tell you this, but the potato is no good for eating anymore! Throw it out.
Option #7: White Vinegar Soak
Another hair-raising option for people who have learned to fear its corrosive properties, white vinegar can nonetheless be put to good use when we want to remove a stubborn rust from a badly battered blade.
All you need to do is get some white vinegar and pour it into a container that is deep enough to completely submerge the blade of the knife or the entire knife depending on what you need to clean up.
Do the following:
- Immerse blade of knife in vinegar.
- Leave it to soak anywhere from 30 minutes to 2 hours.
- Remove knife and it clean using any of the methods one through three above depending on severity of rust.
- Observe it for removal of rust using clean cloth or towel. If no visible improvement, soak again for another hour or two.
- Repeat step 3.
- When all rust is removed, thoroughly rinse and wipe down knife, then relubricate.
And a word of caution here: you must never, ever forget about your knife if you’re leaving it soaking in a white vinegar solution. If you leave it overnight you’ll come back and it will probably be a badly rusted hunk of metal that is beyond saving.
Option #8: Naval Jelly
When a knife is severely rusted and you have tried everything else, you can pull out the naval jelly. Naval jelly is a borderline nonsense term for what is basically a phosphoric acid solution, be it a liquid, a foam or an actual gel.
Renowned for its ability to strip rust off of basically anything, you’ve definitely got to use this stuff cautiously, gloves, mask and all. Also, a little bit goes a long way and it can hideously corrode both carbon and stainless steel if used carelessly. Nonetheless, when you really want that rust gone, reach for this stuff but only after you’ve tried the other techniques on this list.
Do the following:
- Make sure you have your safety equipment on.
- Coat affected areas with naval jelly.
- Allowed to sit for prescribed time according to package instructions.
- Use steel wool, fine wire brush or other scrubbing tool to scrub affected area.
- Add more naval jelly as required.
- Periodically wipe off knife with cloth or rag and observe for removal of rust.
- Reapply and continue scrubbing as needed.
When finished, rinse, dry and it really lubricate knife completely. Ensure that no trace of naval jelly remains.
Got It Off, Now Keep It Off
And I’m not talking about the weight that is keeping you from squeezing back into your fighting trim blue jeans.
Once you have removed the rust from your pocket knife, you can save yourself a ton of ass pain by taking steps to prevent the rest from accumulating again.
This is easier said than done if your knife was pitted by said rust because those pits easily trap moisture and help the rust erupt again.
Consider the following steps and options for preventing rust on your knife or perhaps rust proofing it entirely:
- Keep your knife lubricated. If you make the weekly or bi-weekly lubrication of your knife one of your typical end of day chores, you’ll start to enjoy it and your knife won’t rust. Compared to a firearm, it takes only seconds to lubricate a knife enough to prevent corrosion.
- Knives that are used or carried in hostile, corrosive environments must be cleaned and lubricated far more frequently than ones in less hostile environments. By the same token, knives that feature especially vulnerable steels or finishes must be maintained more often likewise.
- Don’t keep your knife in any kind of case, pouch or other soft container any longer than you have to to carry it or make use of it. Soft materials soak up moisture and keep it against the knife that they carry, exacerbating rust. Leather is awesome, but a serious perpetrator in this regard.
- You might consider having your knife refinished with any number of hard use finishes that will greatly reduce the chances that rust can form, at least on the finished parts. Certain non-metallic finishes cannot rust at all, greatly reducing maintenance concerns and worry so long as they are applied correctly. Your local bladesmith or dealer can direct you.
Any tool that we carry and use often will be subjected to its fair share of rusting and this has ever been an issue for our constant companion, our pocket knife.
Rust is just a fact of life, but you needn’t sweat this aggravating inconvenience now that you know how to deal with it however minor or severe it might be.
A few minutes time and a tiny bit of elbow grease are more than enough to banish rust and restore your knife to beautiful, lovingly used condition, ready to go to work again.
Tom Marlowe practically grew up with a gun in his hand, and has held all kinds of jobs in the gun industry: range safety, sales, instruction and consulting, Tom has the experience to help civilian shooters figure out what will work best for them.
2 thoughts on “8 Ways to Get Rust from Your Pocket Knife”
I just stick rusty tools in a bucket of WD-40 and let them soak.
Then pull them out, spray on Bike Chain cleaner , wipe it clean and then lube with appropriate lube for the tool.
I bought a gallon of WD-40 @ NAPA auto parts.
I use the black super fine sand paper. I have some collectors knives. I wax them with auto wax after removing rust.