Any idea how to clean this

[Lareon]

This is from a sword I posted recently.

 

It has some kind of staining on it. Looks chemical of some kind. but isopropyl and cleaning don't work at all. I've just oiled it and put it away for now. 

 

I tend not to do too much cleaning of the blade except oil and a light clean but this one is really bothering me.

 

Would love to know if anyone else has seen this or know how to remove it.

[Ray Singer]

It is best to have a professional togishi evaluate. 

[Lareon]

7 minutes ago, Ray Singer said:

It is best to have a professional togishi evaluate. 

 

Probably not going to got that far. Unless it's something simple I'll just be leaving it as is.

 

Just wasn't sure what it was and thought maybe someone had seen similar

[Bruce Pennington]

It's the most staining I've seen on one blade.  I have several blades with spots, like you showed on the other side, and I've had no success in getting them off.  It's like a stain that is embedded into the steel.

 

You can try 90%+ alcohol, but in my experience, it's only shined the surface but didn't remove the black stains.  Unless someone has some magic cure, I agree with Ray that only a polish will solve it.  There ARE cheaper versions of polishing.  You don't have to pay for the most expensive kind.  I'm not experienced in the terms, but when I had mine polished there were 2 or 3 versions I could pick from and some were cheaper than others.

[robinalexander]

Tony, I have a blade in 94 mounts that looks the same (covers the whole blade).

 

It is what it is but that sometimes comes with 80 + years of age.  Some may call it patina but whatever you want to call it, I agree with Bruce and Ray. Some 'soft' cleaning products will put a glow on the metal surface (i.e. Nevr-dull) but I am not aware of any that will lighten let alone remove that black staining so either enjoy as is or go down the professional polish path.

 

[Brian]

Uchiko over a long period of time.
NOT recommended for any sword in even fair polish. But for something like this, it can't hurt.

[Lareon]

Thanks for all the replies. Yes the stain is embedded into the steel and I'd rather leave it I think. They all have their quirks. I did consider uchiko but I think I'll leave it in its roughly found state.

 

Cheers again!

[Stephen]

It's called oxidation and whatever you try to do will just make it worse.

[Stephen]

if you want to make it shine....his first introduction tells you all .... One of the ingredients is abrasive and in all kind of cleaners you are going to find to remove oxidation, so don't let temptation get the best of you👍

 

 

 

 

[ROKUJURO]

Tony,

unprotected carbon steel surfaces are very reactive with different agents. Besides water or moisture, your discolourations might have been caused by household vinegar, blood, orange juice or any other fruit or vegetable juice, salt water, saliva, chemical vapours of acids and halogens a.s.o. Even an accidental short-period contact could affect the surface, and when you wipe the surface 'clean' immediately, it might even be too late to avoid staining. 

Usually, this layer of corrosion is not thick, and will be easily removed by a trained TOGISHI without loss of much material. All abrasive agents you may have at hand will work fine and also remove the discolouration, but they have a serious drawback: they will also take metal off where they shouldn't: on the SHINOGI and other usually crisp angles which are the sign of a well cared-for blade. As a consequence of an inappropriate grinding of a blade, any additional authentic polish will mean to take more material off the surface to restore these crisp angles.

It is important to remove active red rust as this 'eats' away the steel, but this unwanted 'patina' as you show it on your blade is not dangerous as long as it does not change its state and get worse. 

Chemical solvents (alcohol, acetone, trichlorethane, nitro thinner, ether, paint stripper and alike) will only do what they are made for: Dissolving chemicals which may appear as paint, plastics, grease, oils, and more of that. They will work with organic chemicals but mostly not with anorganic chemical compounds of metals or minerals. 

So you may remove any paint from a blade without affecting the metal, but any form of corrosion (red, grey, or black) will require a polish by the hands of a TOGISHI.
 

[Lareon]

Cheers all, I will just leave it as is, thanks for the help and comments.