appreciate all the information. This has definitely led me down a rabbit hole in terms of reading which is great. I gave the blade a light wipe with isoproyl alcohol using a coffee filter and then wipe down with a cotton cloth and a very light amount of 3 in 1. The rest of the fittings and the saya just a wipe down with a clean cotton cloth. I have it reassembled without any issue. One of the meguki's was previously broken..so it's only about half as long as it should be. Any recommendations on replacement or leave as is?
Also...curious on thoughts around fabrication. I came across an article that describes the 9 manufacturing methods of that time period as per Richard Fuller (listed below). Where would this blade fit into that? I am assuming somewhere between 4 and 7. Is there any general rules around when a smiths signature would be applied or not in regards to the manufacturing processes listed below?
1. Tamahagane gendaito. Fully hand forged and differentially hardened in the traditional manner using water as a quenching agent. Possesses an active hamon and hada.
2. Mill-steel gendaito. Fully hand forged from mill steel or (more often) 19th century railway tracks made from Swedish steel. Differentially hardened in the traditional manner using water as a quenching agent. Possesses an active hamon and hada.
3. Koa-isshin Mantetsu-to. Made from Manchurian steel by a special process. Partly forged, partly engineered, and differentially hardened in the traditional manner using water as a quenching agent. Possesses an active hamon and hada.
4. Han-tanren abura yaki-ire-to. Partially forged from mill stock, some folding, differentially hardened using oil. Does have a hamon although it is nowhere near as active as a water-quenched sword, but lacks hada.
5. Sunobe abura yaki-ire-to. Drawn down, forged to shape, not folded. Differential hardened using oil, may have a fairly inactive hamon, but no hada.
6. Mantetsu-to. Rolled from Manchurian railway tracks. Differential hardening using oil, may have a fairly inactive hamon, but no hada.
7. Murata-to. Rolled or drawn, oil hardened but not differentially hardened. Yakiba but no visible hamon and no hada.
8. Tai-sabi-ko. Stainless steel, oil-hardened, no grain, no hamon, possible yakiba. Made for the Imperial Japanese Navy to resist salt corrosion.
9. Machine made. Serial number in the blade. No forging; stamped out and quenched in oil without differential hardening, assuming that they are hardened at all. No hada and no hamon. Some may in fact be plated, and in the worst cases the hamon may be acid etched onto the steel. The classic example is the NCO swords. On a par with Chinese fakes, and the most commonly faked sword.
(list was taken from the following article: http://ryujinswords.com/shostamp.htm)