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Question:
With all of the "green cancer" on copper pennies these days, has anyone experienced this getting worse over the years as the pennies are stored.
I have only been storing pennies for a couple of years. The environment is fairly humid. I store the pennies, loose, in the mint boxes I receive them. I know that the humidity will go thru the box. Will the green cancer grow over time? Will I just have boxes of green cancer 15-20 years from now?
Any experience or help would be appreciated.

Cent1225, this was your first post! Welcome fellow copper hoarder.

Unfortunately I don't have an answer and I too am curious. My coppers are rolled in the paper rolls and stored in the $25 Brinks boxes. Should I be putting a silica gel packet in with them? All info welcome.

Water, acids, and copper oxidize, I don't think the zinc's will turn green. If they are not green to begin with they should stay brown. All the grime they picked up over the years keeps them protected. I'm not a storage expert either but I would try to keep the humidity at a reasonable level, as long as they stay dry they should be fine. I did not want the extra work to re-roll and box, I'd go for 1 or 1.5 gallon jug sizes so more can be carried easily yet sealed, and maybe later stored outside, or in the garage, wherever.

I appreciate the quick replies about my question. "Everything" made a good point about sealed in plastic and keeping the humidity down. Got me thinking about vitamins come with the little packet of dessicant. Found a web site for these little packets, they are cheap; only 19 cents each. I plan on getting some an putting them inside the sealed container with the pennies. Should remove any remaining moisture since the pennies take up most of the space.
For info on the packets, go to: http://www.silicagelpackets.com/silica-gel-packets/

If you store your coins in a somewhat air tight place. There is a device called a Golden Rod. It is designed for gun safes and it keeps humidity out of a gun safe. They are about 30-60 dollars depending on which one you buy. I bought one at Bass Pro Shops for 30.00 and its made by Browning.

Keep Sorting
Mongo

PVC storage makes for the green gunk becasue it breaks down. Store the pennies in polyethylene or Teflon and they shouldn't rot away like that.

I've seen zincs in circulation with the green gunge on them.

(The generic term is "verdigris", it can be one of several copper compounds.)

Cent1225 wrote:Will the green cancer grow over time?

I believe it will. Every so often I open rolls but leave the coins in buckets for a week or two before sorting them. Several times I noticed that when I found a slimy green penny, the verdigris was also growing on the adjacent coins. I've seen this in rolls, too.

tinhorn wrote:

Cent1225 wrote:Will the green cancer grow over time?

I believe it will. Every so often I open rolls but leave the coins in buckets for a week or two before sorting them. Several times I noticed that when I found a slimy green penny, the verdigris was also growing on the adjacent coins. I've seen this in rolls, too.

Myself, I though that the gunk meant the penny came from a body or car-mechanic shop.

If the green cancer is oxidation caused by oxygen exposure then possibly the oxygen absorbers used in long term food storage may do the trick.
The container would have to be very well sealed after adding the proper oxygen absorber based on the container size. When I sort, if a penny has even a little bit of green it goes into a bath of CLR for a few minutes when I have a few bucks worth, then rinsed and air dried prior to rolling. Lately it seems like a lot of the coppers have some on them and the zinkers have been pretty bad too. They are mainly like that in string rolls where the rub into the real ugly ones in the rolling machines.