Extreme oxidation / corrosion question

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Hey guys, not much of a welding question but has to do with oxidation / corrosion, I stumbled upon my great grandfather's wallet (he died in the 70's) in my home safe, I was surprised I had it! Among a very old social security card, an ancient Nebraska drivers license, an AA card, $50 state farm insurance for a 1964 Buick, and an air martial certificate I found a very, very old key. Here's the interesting part its been sitting in this old wallet in a plastic bag in a safe for the better part of 45 years and its covered in this strange green stuff (see pics) No idea what caused this or what the base metal is (I assume brass). If anyone could provide some insight on this oxidation or corrosion that appears to have happened I would greatly appreciate it! thanks




Reply:Depending on the tanning process, various chemicals remain in the leather. They leach out and attack the metal (yes, brass), forming copper compounds that give it the blue or green color. I don't know if the gummy material was originally fatty compounds from the hide, or from the tanning process. Same thing happens with brass rivets in leather holsters, and I believe the time it takes to happen is reduced with increasing humidity. Acids remaining in old (cheaper) paper can similarly break down the fibers, causing the paper to fall apart if not stored under super dry conditions. Newspaper is a common example. If you want to clean the key, try using a solution of ammonia. Maybe document it with a camera and post pictures of both the key and the solution, taken at a few intervals over a period of half to a full hour.
Reply:Soak the key in hot sauce or catsup.   Should come clean.Sent from my SM-G975U1 using TapatalkLincoln 175Monkey Wards 230v.  Stick
Reply:Vinegar typically does job. Remember do not leave in the Vinegar for a long time or key disappear Dave

Originally Posted by porous_weld

Hey guys, not much of a welding question but has to do with oxidation / corrosion, I stumbled upon my great grandfather's wallet (he died in the 70's) in my home safe, I was surprised I had it! Among a very old social security card, an ancient Nebraska drivers license, an AA card, $50 state farm insurance for a 1964 Buick, and an air martial certificate I found a very, very old key. Here's the interesting part its been sitting in this old wallet in a plastic bag in a safe for the better part of 45 years and its covered in this strange green stuff (see pics) No idea what caused this or what the base metal is (I assume brass). If anyone could provide some insight on this oxidation or corrosion that appears to have happened I would greatly appreciate it! thanks




Reply:Did he drive a Ford?
Reply:That may be a key to a safety deposit box.  Other options for cleaning are an ultrasonic cleaner and/or vibratory tumbler.Miller Trailblazer Pro 350DMiller Suitcase MIGMiller Spectrum 2050Miller Syncrowave 250DXLincoln 210MP
Reply:Looks like the key to his Buick to me.  Sweat salt in the wallet responsible for the corrosion.CG