Rust inside ware?

[Totoro945]

Have bought a Mihara sword couple of years ago on this forum. It has some ugly mune ware near nakago, but as I've heard it should not be a big surprise for a 600-year old blade. Otherwise the blade is a beauty.  What concerns me is a red rust spot visible inside one of the ware. Is it a serious problem? Should I just contain it with oil, or try to fight with something like Renaissance Metal De-Corroder or Never Dull? Any advise is welcome!

 

Thank you,

Vadim

[16k]

I’ve never had to deal with that and, to be honest, I don’t see the red rust in your picture. Now, if there is some, my first action would be to try and wash it off with oil and maybe scrape it with a needle and oil again.

[Guest]

Not a needle, perhaps some bone or antler shard?

[Totoro945]

Please see a larger picture attached, it is more of a red-brown color. It is not spreading outside, but who knows what is happening inside

[Ray Singer]

I would be inclined to *carefully" remove the flaky active rust with a brass pin. I have used soft metal pins (like those on the backs of brooches) to scrape out red rust without damaging the surrounding polish. Using a pin will allow you to get into the area, but as said above it is uncertain how deep the damage goes. Quality Japanese togishi will sometimes fill voids like this will lacquer after they have been cleaned out to prevent rust from returning. 

[Ken-Hawaii]

At least make sure those voids are filled with oil.

[Vermithrax16]

Antler works best in my experience but solid advice here. What I wonder is what happened to that side of the mune? Besides the openings there seem to be severe scratches on the blade. How is this sword stored, shirasaya or koshirae saya? Seems something at some point was causing pressure and friction.

[Totoro945]

It is stored in koshirae. The scratches probably appeared over time by taking in and out the blade. They do not look really that bad uder normal conditions.

[Totoro945]

Just looked again under a really big magnification and it seems to me this is not rust at all, but indeed some paint or laquer! Thanks Ray for mentioning this possibility, I am so happy that I have not scratched it off!!!!!