Yes you read that right. Went back to the 5 for a dollar bin and found this. Since I bought some other coins, my son got this for 10 cents!
For 10 cents, you can’t go wrong, but the coin is corroded. The copper coins usually have green corrosion; the copper-nickel pieces have what you see here.
I would have grabbed it even without the 50% discount. Are you saying that something needs to be done to the coin to conserve it? I've got quite a few copper-nickel coins in this state, but I've assumed that as long as they're kept dry, they're stable. I've certainly seen no evidence of progression, or even any flaking from the existing deposits.
Really nothing can be done to conserve the piece. The best you can do is store it in a dry environment are steady temperatures. I’ve seen coins that were stored in basements, garages and attics, and the results were usually not attractive.
As I was saying before all four replicated posts got cleaned up ... I didn't mean to suggest a coin like this could be improved by "conserving" it. I just don't think it needs any special treatment to prevent further damage. It is what it is. (And to me, like other FECs and early IHCs I have in similar condition, it is collectible!)
You'd be surprised at you can find in foreign coin 5 for a dollar box I have found a dateless shield nickel and an Irish Conder Token.