Spots on a coin - what is it and how can I stop it?

This is the same coin, before (when I got it) and after (now). The coin came in a flip, and I left it there for a few weeks before putting it in an airtite.

From what I've seen around here, these brown sports are not PVC damage. I guess my title says the rest.

Thanks for your help.

 

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Hi Luis, the spots will probably not go away, depending on the material of the coin it will act like cancer. There might be something that will halt the spot but I am not knowledgeable enough to know it.

 

It's a silver coin. I figure it will not go away, I just want it to not get worse.

 

Most likely it is a sulfur compound reacting with both the silver and the 10% copper ( I assume tat is the other 10%). A "Dip" might not remove all, and would not be advised. To preserve, I would rinse with acetone ( or if that seems a little too strong for you, 90% isopropyl alcohol is available at Walmart and other pharmacy areas) and then after air drying, put into the storage holder. The continuation will depend on the environmental factors of humidity and gases where stored. The airtite holder will help a lot, but is not air or humidity tight. If it can be replaced inexpensively, I would do that anyway if the spots bothers.

Jim

 

I agree I don't think there is anyway to stop it unless you encase the coin and keep it in a safe box with air absorbtion.

 

Jim,

The coin was about $20 I think. I'm not very bothered by the spots. I think they're kind of noticeable mostly because it's a proof coin. I just don't want it to go worse.

What exactly do you mean by rinse? Which safety precautions should I observe when dealing with acetone or 90% isopropyl alcohol? Why wouldn't dipping them in these substances work?

I have the airtites in a plastic container (PVC free) with rechargeable silica gel.

Thank you for your help!

 

Generally, I rinse coins I have just received unless they are slabbed with acetone. Usually I do this with all I intend to keep , as fingerprints or other organic material may be invisible and yet there. There are different ways and procedures from multiple steps to putting the coin into a glass container of pure acetone ( like from walmart paint section), let it set there for a few minutes ( 5-10) and then hold vertical and pour fresh acetone over it so it drains into your glass container. Acetone will also remove any residual water and vapor inside any crevices. Let it air dry ( takes seconds) and then put it into a safe holder. Just a general precaution.

Jim

 

Thanks for the replies, guys. I will buy acetone and read on the site about safety precautions. I know the info is around somewhere, I've read it several times.

I never had any "saliva problems" that I know of. And this is more surprising if you think I never took any precautions regarding that potential problem.

I figure I'd be more annoyed by all this. I might get another eventually.