Green mold?

tyr_shadowblade

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Jan 3, 2006
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11,281
So far, 2 knives I've gotten off eBay had some sort of green mold on the handles. Both were Sharpfingers in leather sheaths, and the mold was on the side of the handle that was in contact with the leather.

One had a pommel hole that was completely clogged (I sent that one back), and this new one has it around two rivets. Seller said that was "normal" for brass rivets, but these are nickel plated and it appears to be mold rather than oxidation.

Mold is blueish-green, thick, sticky, and putty-like. Has anyone else run across this problem, and what's the best way to clean it off? (Of course, I'll be disposing of the sheaths, even though all I see is a small bit of discoloration).

Thanks.
 
Joined
Dec 31, 2000
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It's natural, and happens when the knives are stored in the sheaths for long periods. As to what it actually is, mold or oxidation, I have no idea and generally refer to it as "green gunk."
 
Joined
Jan 30, 2003
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I believe this substance to be verdigris. Even if the metal is nickel plated, there may be copper-bearing brass underneath which, when oxidized over time, produces verdigris.
 
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Dec 28, 2007
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that's called patina or in the case of copper, verdigris. it forms naturally when the metal is exposed to air and it's harmless, in fact it is very effective at protecting the surface from weathering. The best example is the Statue of Liberty.

from wikipedia : Patina is a coating of various chemical compounds such as oxides or carbonates formed on the surface of metal during exposure to weathering. The green patina that forms naturally on copper and bronze is known as verdigris and consists of copper carbonate. One example of a patina is a green surface texture created by slow chemical alteration of copper, producing a basic carbonate. It can form on pure copper objects as well as alloys which contain copper, such as bronze or brass.
 
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Jan 10, 2003
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I usually find it where the brass guard has been in contact with the leather. Brass snaps form some also.
 

riversidedep

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Nov 27, 2007
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My understanding is the leather retains some of the chemicals used in the curing process, such as tanic acid, which reacts with the brass to produce the verdigris. The verdigris is pretty harmless, but is unsightly. This is one of the reasons one should avoid storing knives in leather sheathes.
 
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