All About Pocket Knives

A friend gave me this Bear and Bull knife tonight, and I am very puzzled by it.
We were looking through a box of his pocket knives, and I spotted the corrosion on it. At first I thought that it was outgassing, obviously. But it has bone handles! I took the knife home and even scratched a bit off of the bottom edge, and the handles are jigged bone. He has owned this knife for several years after inheriting it from his uncle. He did not remember any corrosion before this.
It was in a box with an older Hen and Rooster that had yellow celluloid handles, but they looked bright and perfect - no discoloration or shrinking. None of the other knives in the box appeared to have any corrosion.
I explained celluloid to him and he is now storing the Hen & Rooster away from his other knives, but I am puzzled by this one. Any ideas on how it came to be like this?

That's weird that the corrosion seems to be associated with the bone...if something else was outgassing near it, I would expect to see the exposed portions of the blades to be more affected.

I totally agree with Glenn. I don't see any of the normal signs of outgassing. Perhaps this knife was put away wet or at least damp at some point?

My 2 cents: The out-gassed celluloids I have had usually have a rusty=red patina that buffs off fairly easily. It's not a pitted corrosion. I can't tell from your pics but it looks a bit crustier than a simple patina. How about buffing it off and watching it to see if it returns? (might take a year or more.) Maybe the knife was soaked or dropped in some chemical? Salt water? The blades appear slightly pitted, or is that a smudge or reflection? God luck. J.O'.

Very strange. I had a similar unexplained occurence with a Case Classic Stag handled knife. The corrosion occurred over about a two month period, and was limited to the tang area under a swing guard. I blamed myself. I figured that somehow I must have dripped something on the knife when putting it into a display. As it has not happened again, I am still blaming myself for a momentary episode of carelessness. Nothing else makes sense.

After working in my younger days in a chrome plating plant working with different acids this looks to me like a reaction to acid fumes ,it dose not take much for the fumes to settle and start working. Just my two cents

Rev: Found this one with the same situation. Even the pins show verdigris corrosion. J.O'.

Ridgegrass wrote: ↑Mon Oct 16, 2023 9:07 pm Rev: Found this one with the same situation. Even the pins show verdigris corrosion. J.O'.

Yes, similar look and similar pin corrosion. Is that a Bear and Bull knife, or something else?

No, it's some kind of a KA BAR knock off, I call it the "mystery knife". ??? I have an idea that maybe some kind of cleaner or polish may have been used on the bone and collected in the tiny spaces around the bolsters and pins. Just a stab at it?? I'm going to buff it off and watch it for the next ten years
J.O'.

Sounds as good a theory as any. I had begun to wonder if there is glue beneath these handles that might put off fumes? Probably not - I don't think that many manufacturers use glue.
Yes, we will go with polish unless we find something else definite. Thank you!

Is it possible there were impurities in the metal that would account for this? Just curious since I’ve seen some odd things on knives over the years.

Could it be related to how they dyed the bone? Some dyes may be corrosive.