BamaJoe wrote:Half Box #151
1 1967
Ok, I have a question for you experts. What is that nasty green stuff that grows on the coins? This box was just filthy and covered in the green crap. I only spotted the one I found because I saw a glimmer of silver where the coin had been nicked on the side. Still had to use the rim of another coin to scrap the grunge off of it enough to see the year.
Should be mostly Copper (II) Chloride. It is a green salt that also absorbs water; probably your box had been exposed to excessive humidity for an extended period if the salt was particularly gunky and nasty.
Apparently Nickel (II) Chloride is yellow when anhydrous and becomes green when hydrated, although it mostly takes the form of the hexahydrate, NiCl2 * 6 H20. Because this is a rather large amount of water, I find it more likely that you are dealing with Copper (II) Chloride. Take care however, as nickel salts are apparently carcinogenic. I can tell you however, that I have encountered small quantities of anhydrous Nickel (II) Chloride, as I have seen the yellow gunk before, but it is less common.
However, bear in mind that Nickel is more readily oxidized than Copper, so this increases the chances that the green goop is in fact a nickel salt, and not a copper salt. Can you send us a picture of these coins, as I am now quite curious to see them? There is a way to test for whether the green stuff is in fact copper or nickel. Basically this requires putting the green gunk in a solution of hydrochloric acid and then adding a metal that is more reactive than copper, but less reactive than nickel, with tin being a good choice here. If the tin reacts, than the copper will come out of solution as the red metal and this will be obvious. If the tin does not react, then you have nickel. It may be useful to know, as nickel salts are dangerous to human health, far more so than copper salts.
I'm going to go a bit further here and speculate that the green crud is in fact a copper salt and not a nickel salt. The reason for this is because I recall a particular 40% coin which had quite an accumulation of green salt stuff. Obviously, that coin contains no nickel and plenty of copper. So it's probably Copper II Chloride for this reason.