Rust if left out of saya?
QUESTION: I understand that blades will rust, which is why you have to oil them before sheathing them. Does leaving them in the sheathe speed up the rusting? Will it rust more slowly if left unoiled in the sheate or unoiled outside of the sheathe?
I don't think it will make much of a difference really. If you leave the Katana in a saya, it may become humid and rust. If you expose the blade, dust particles will soak up the oil and leave nasty little spotty stains at around
the same rate (roughly).
In most climates, assuming the sword is well oiled to begin with - you don't really need to oil that often. My original PPK has been in the saya for around 6 months without taking it out and no rust (that's in the cooler months). Much depends on the climate.
Hope this helps.