Removing small amounts of rust on nicer blades

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Senior Member
Jul 3, 2022
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Hello everyone,

Sorry if this is a “duh” question but I usually just take my rust erasers to whatever knife is giving me problems.

My question has to do with nicer finishes on some knives in this case my Hado “shiro” gyuto. It has some small amounts of rust forming and is very superficial. Should I just be using my fine rust eraser on it and just have at it or should I be looking into uchigumori finger stones, powders, fine wet/dry sandpapers to slowly take off the spots and refinish it.

I don’t mind just going at it with an eraser but as I’ve been purchasing the next “tier” knives I’d like to know what you guys use to spot check some fancier blades without ruining the finish.

Any tips/links to videos are appreciated.
Flitz or Simichrome. If that doesn't do it try Bar Keeper's Friend (powder not the cream/soft cleanser) but be sure to rinse thoroughly or follow with an alkaline like baking soda and then rinse. Bar Keepers Friend does include a mineral abrasive and IME is more likely to leave slight scratches than Simichrome or Flitz. I'd pick any of those over a Rust Eraser, even the "fine".
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2nd the Flitz recc. It might change the sheen slightly on kasumi but if it bothers you then you can bust out the uchi powder.
Where do you get the uchi powder? I’ve seen some misleading options and didn’t want to buy something fake.

Also what do you normally end up applying it with? Like a polishing rag piece?
I recommend 1500 grit silicon carbide powder. Trey (Comet) used to include a small pot of it with his knives to remove small water marks and patina without affecting the finish. Its works great. Use as a dry powder or mixed with a little oil. Worked great at eliminating minor rust spots.

Vendors on Ebay.
I use koyo blue compound stainless/metal polish for cleaning up my blade everyday. You can try that or just use Flitz or any metal polish you have in your area and rub it with cotton pad
I routinely use crocus cloth (iron oxide powder on clock backing) on my customer's knives to remove spots and have never seen them leave a scratch. I only see littles stains or spots, so I've never tried a truly bad rusted knife which would be a horrible thing to resurrect.
I think going with the mildest options first are your best bet. If flitz, or semichrome doesn't work, and neither does barkeepers friend. Then depending on the finish, you can get different grit abrasive powders on amazon fairly cheaply. I'm not sure what the finish on the blade looks like from the factory, but I'm sure there are people here that can help guide you through restoring it.
Thought I'd add a bit here in case it's helpful. I picked up an Ontario Rat Model 1 made with AUS-8 that the previous owner had definitely used as a work knife with little if any care or maintenance. I grabbed it as a $5 challenge and among the issues was some rust on the blade. It was not rusted to the point of pitting. I did a fair researching using my google-fu and there are many ways to go about it but I what I tried first because it was simple and on hand was White Vinegar and it worked rather well. I soaked the blade overnight and most of the rust was gone the next morning. Soaked for rest of day and almost everything was gone. I've also heard that Apple Cider Vinegar and Cleaning Vinegar (also white but less diluted) work well. Odds are good that you've got this around the house already and it's a no-scratch solution if it works for you.

*** I know that the vinegar worked well on the AUS-8 but no idea if there would be a chance of any special finish on your knife would be affected so I'd research it a bit or maybe do a small test on the tip of the blade or something if you're not sure or just want to be extra careful. ***

Any "polishing solution" like Flitz, Simichrome, ... etc. are technically going to affect any existing scratch pattern so while I would also recommend them I'd make that choice 2 or 3. Should be ok if it's a polished finish but I'd check. Worst case you have to do the whole knife if a difference shows up ... or just live with it.

Here's a couple links to videos where a guy tested like 8 or 10 things in each video and gives a summary of his results. Note that in one of the videos he uses Arm & Hammer Washing Soda - that's different than "Baking Soda" (Sodium Carbonate vs. Sodium BiCarbonate) but I've heard/read that both will work but the Carbonate might be a bit quicker.

Which Rust Remover is Best?!

Which Rust Remover is Best?! Part 2

BTW - main reason for my $5 challenge was a fairly well chipped and useless blade that I could learn to sharpen and deal with chips without any major investment in case it all went south. Sharpening, rust removal, tear down/clean/lube and the end result after some love is an awesome $35ish knife :)

Hope this helps and again ... whatever you do, consider trying a little test spot first.

Baking soda+lemon juice paste

Just to add in addition to my previous post that I've also heard that combining some things as @M1k3 suggests works rather well. I think the lemon/lime/xxx juice ingredient that works is the citric acid (?) and I've seen those mentioned as a rust remover. Adding the ingredients of the baking soda (or washing soda) is supposed to give you more bang for the buck. I've also seen the same suggested mixture with vinegar. I've never tried it but it makes sense.

A word of caution - I've read somewhere to use salt with a solution or to sprinkle on the steel and then rub - I'd be careful of that since the salt would be an abrasive that if rubbed could affect the finish of the blade. I don't know if the combined chemical makeup of the salt is supposed to add to the rust removal properties or not ... use your goggle-fu for that answer.

One other thing - regarding application - rather than soaking in a jar/pan/... etc. I've read that wrapping the steel in a paper towel and soaking it with vinegar or whatever you're using (eg lemon juice) also works. Could be helpful with a large knife for example. You could also make a limited size container with something like plastic or aluminum foil (or both) so you didn't need a huge pan/vessel and could also protect the handle from being exposed to whatever solution you might be using.

Hope this is helpful ....

What you just said is 100% completely incorrect.

Have you not seen any of my work?

Depending on the knife I use one of those three methods to achieve the final finish.




Hard abrasives will immediately destroy the shine on the side of a polished blade. Most knife owners don't want to do that.
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Saw @EricEricEric post and at first thought he was talking about my post ... glad that's not the case. Very, super nice, beautiful work there Eric! Note to self - don't mess around - send knife to EricEricEric! :)

I thought I'd post a before and after vinegar pic of the blade that I mentioned above. After pic also had some light scotch brite pad work done to remove scratches but I stopped there as a work in progress. Pics are just intended to show the effects of about a 24 hour soak in vinegar on rust.


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The big difference here is he is cleaning a carbon steel blade. Soaking it like that in vinegar is going to cause a dark oxide layer to form. While that can also potentially happen with something like aus8. It will me much milder, and easier to remove. Those kind of soak times are basically going to lead to them just having to completely republish the entire blade. It's going to likely leave the core steel near black in color and the cladding much lighter.

That can be removed obviously, but like I said that's going to have to be done by just polishing the blade, which will for sure completely change the appearance of the blade. I never saw them post what the blade finish actually looks like, so that can be difficult to advise them on.
Yeah, AUS-8 is stainless. There's no way I'd soak a carbon core knife in vinegar or anything else for that matter. And I would also not use salt in any form.

I'm a BKF kinda guy.
Finger stones, stone dust, or 15-50k diamond powder all on a small felt pad
Precisely! Why would anyone use anything reactive or heavily abrasive, your just going to create another mess that will need to be cleaned up. KISS...

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