I have an ontario pilot survival knife from 1980. My uncle who wanted to become a pilot was given the knife from some air men in the 80's. It also has a mismatched sheath from the 60s or 70s. The knife proceeded to sit in my grandparents basement until I found it more than 30 years later. The many years have not been nice to the knife, its leather feels brittle and its blade a bit rusted. I have mostly fixed the rust issue but how should I go about fixing and preserving the handle and sheath. Also what type of steel is used on these knives? From what I can tell its 420hc with some sort of bluing. Whatever finish the knife had, it mostly worked.