What Causes Greenish Mildew? - Coin Community Forum

To participate in the forum you must log in or register.

Author	Replies: 6 / Views: 2,184
North of 49 Pillar of the Community Canada 617 Posts	Posted 01/21/2014 7:58 pm Noticed some greenish ( mold?) on some of my half dollar coins the other day . Anyone have any idea what might cause this? I would like to hear some thoughts although I think I might already know. I'm thinking it may be cause by one of three things, the plastic sleeves I use, the plastic containers that I keep the plastic sleeves in, or it might be the cold place I keep my coins in. And how to clean this mold off , gently rubbing with a soft cloth? Report this Post to the Staff

nalaberong Pillar of the Community Canada 2805 Posts	Posted 01/21/2014 8:01 pm Is it light green? It's likely to be PVC (polyvinyl chlorate) plastic residue. This nasty stuff is predominant in older plastic, and is still very common today - without PVC, most plastic becomes much more brittle and breakable. It is slightly volatile and reacts terribly with silver and copper, leaving behind a nasty green residue. Acetone (PURE acetone from the hardware store, not nail polish remover with extra perfumes and things) should get it off. Some other members should know the correct protocols for this. Report this Post to the Staff
torgemco Pillar of the Community Canada 1046 Posts	Posted 01/21/2014 8:17 pm hi nof49 would you have any photos thanks in advance Report this Post to the Staff
allranger Pillar of the Community United States 1391 Posts	Posted 01/21/2014 9:25 pm Do not rub with a soft cloth. The will leave hair line scratches and it will become a cleaned coin. nalaberong is right, if it is PCV gunk, Acetone will take care of it. Report this Post to the Staff
Libertad Pillar of the Community Canada 3692 Posts	Posted 01/21/2014 11:38 pm The higher the copper content, the more this will occur. This recently happened to a few of my coins that range from VG-AU. This is in 2x2 mylar cardboards! Don't kid yourselves! After about 2-3 years your crustier coins will fester. Specifically the coins were: - 1950 50 centavos (Mexico, .300 fine) - 2x 1940s Canadian Half Dollars (.800) - 2 Swiss Francs (AU, .835 fine) The coins with the lowest fineness were affected the most. When the surface of metal gets rubbed, scraped, manipulated in any way, the grooves in the metal allow for more tarnish I believe. A mirror finish is one where you cannot see striations in the metal under magnification and you can see your own face. Once the metal surface is compromised the atmosphere affects it faster reacts with the copper. Report this Post to the Staff
lambecolin Pillar of the Community Canada 618 Posts	Posted 01/22/2014 02:44 am What about VERTIGRAS?------That is permanent damage! Report this Post to the Staff
North of 49 Pillar of the Community Canada 617 Posts	Posted 01/22/2014 8:04 pm Here's a couple of pics of what I'm talking about, they're not the best but they do show what I'm talking about Thanks for the responses and advice. I was glad to see that only my spare coins were effected. So it looks like my first step is to get them out of the plastic holders. Does anyone know, are the plastic windows in 2x2's a different safer plastic? Report this Post to the Staff
	Replies: 6 / Views: 2,184

To participate in the forum you must log in or register.

All Forums Category: Canadian Coins and Currency Forums Forum: Canadian Coins and Colonial Tokens

Silver Gold Bull US is the United States leading bullion dealer. We deliver gold coins, gold bars, silver coins, silver bars and precious metals to your door. Order today!

The First Dollar, your premier source for bullion and rare coins. See our bullion list on the site and the coin inventory on ebay.

View Last 100 New Topics

View Last 100 Active Topics

Disclaimer: While a tremendous amount of effort goes into ensuring the accuracy of the information contained in this site, Coin Community assumes no liability for errors. Copyright 2005 - 2026 Coin Community Family- all rights reserved worldwide. Use of any images or content on this website without prior written permission of Coin Community or the original lender is strictly prohibited.
Contact Us | Advertise Here | Privacy Policy / Terms of Use

Coin Community Forum

It took 0.27 seconds to rattle this change.