[Nihl]

Not to derail this thread into a conservation vs restoration-type argument, but I have to contend with this overzealous glorification of patina. All patinas are the result of oxidation. All oxidation (in ferrous metals) is rust. From personal experience, most patinas I have encountered either cover up or are interwoven with dangerous, active rust to one extent or another, and said rust cannot be removed without removing the patina.

It is true that past a certain point rust becomes mostly inactive, however this is not the result of the rust "dying", but rather it covering itself up to the point it limits its own effectiveness. A patina is nothing more than the surface of a base metal casually, evenly oxidizing, such that it all turns the same color. This does not equate to any kind of anti-rust armor, rather, patinas themselves are thin layers of rust!

Think of it like digging a hole (which is what rust most often does; bore a hole into metal, resulting in pitting). At the start, progress is easy as there is plenty of room to maneuver oneself. After a few feet, the hole limits movement and prevents one from shoveling out great heaps of dirt in an easy swing. Even when dirt can be shoveled out, there is often a big pile of dirt surrounding the hole, meaning new dirt has to be placed carefully in order to prevent more dirt from falling back in to the hole, which often times happens anyways, further limiting new progress. To decipher the analogy: "we" are the chemical reaction of rust, "digging" a hole into metal. The loose dirt being excavated is metal freshly removed from (in this case) a blade, which has now been turned into ferrous oxide, i.e. more rust. This new rust limits progress as, like loose dirt on the side of a hole, it can fall back into (cover up) the hole, and prevent us from further digging (oxidizing/reacting with the base metal being rusted). This does not mean progress (further digging/oxidizing) is impossible, just that it's much slower. Given enough time and exposure, rust will oxidize enough that the new rust will "push" older layers of rust away, which is what causes rust to flake away and/or turn to powder. While most antiques, because of how they are treated, will not get to this point for 500 years or so, removing oxidation (patina/rust) still resets this clock, instead of passively removing only the most active layer and leaving the rest to further fester and rot. This all gets especially aided by water or humidity, which in our hole-digging-analogy is basically like a bulldozer that removes old dirt & can even be used to create wider, deeper holes.

Basically, what I'm saying is feel free to only remove red/orange rust as you see convenient, but after doing so you better keep that item oiled/waxed or else it very much can and will still rust. Patina does not make an item hydrophobic, immune to the effects of time generally, or "oxygen-phobic" specifically, insofar as it is does not make rust "dead" and possess no further risk.

In terms of what is respectful, I, quite frankly, could not imagine something more disrespectful than handing a warrior a blade with clear signs of neglect! Across cultures, blades invariably were kept as sharp and as clean as possible. This doesn't mean they were all kept to a mirror polish (although there is plenty of evidence that this was preferred too), but at the very least they were not allowed to develop a dirt-black patina! This isn't rocket science: a blade that is neglected and dirty is one that is covered in rust, gunk, and yes, is patina'd.

To throw one more controversial punch: if you need a patina (rust) to tell you that your item is old, and you find it to be so valuable and necessary in dating that you equate removing said patina (rust) to "destroying" the value of an item - you probably don't actually know all that much about your item. Rust **can** be significant in the dating of an item, but all too often it is subject to so many circumstantial variables that it is impossible to rely on it solely as a means of dating something. Form should, principally, be the determiner of age. It is highly uncommon for anything being consistently produced to retain the exact same form or shape over hundreds of years. This applies to reproductions ("fakes") made of older forms too: most often, only with rare exception, the reproduction will not have the same form as the original. I'll end my spiel with some anecdotal experience: I have handled plenty of 19th century items that are many times more oxidized than 18 or 17th century ones. Rust is not a determiner of age, it is the result of negligence.