Question. I am aware you should never clean the tang. But, how do you properly preserve it? The idea of allowing rust to erode a sword’s structural integrity into becoming a  non-functional paperweight over time to preserve a monetary value just throws me for a loop. Not to mention the rust spreading from the nakago past the habaki. Tamahagane is a high carbon steel after all. I am also aware rust is used to date Nihonto but there is no need to date gunto as we have resources strictly outlying d