I've been collecting coins for probably close to two decades. They can be fun - handled all kinds of metals from base metal iron, copper, zinc, to exotic metals such as tantalum and antimony. I've always like to handle coins raw as well as treat them with acetone when they are needed. It's only very recently that there are some coins that I have handled especially some of the older Chinese coins coins that I'm starting to get nasty itches after handling them. Geez they must be loaded with some nasty metal - I just can't figure out what they are. I've handled nickel and cobalt - most common metals to cause allergic reactions. I'm suspecting there's traces mercury in them. I'm sure you can develop such allergies late in life. My food of thought is: how "iron"ic would it be for a coin collector not be able to handle coins in raw? Just thought it's a cruel twist for coin collectors to not be able to handle coins raw.
The only suspicious component of old chinese alloys in coins would be lead. http://www.google.com/url?sa=t&rct=...=ahGnOiuF3q5AOgvf3F2Ptg&bvm=bv.53899372,d.cGE Lead can sensitize many individuals immune system and produce skin and other immune reactions. The reference above gives lead concentration in various chinese coinage. You can compare the ones you are handling to see if it is high enough to cause concern for your physician. Old coins which have formed lead salts would be my best bet. http://www.environmentalhealthnews.org/newscience/2007/2007-0625gaoetal.html
From that article: "Nickel in coins needs to be included in the EU restriction of nickel (REACH) to protect the citizen." How many of us wear nickel coins on their skin every day? There is a reason why the REACH regulation does not cover coins. http://www.numismaster.com/ta/numis/Article.jsp?ad=article&ArticleId=27068 Christian
I have no problem handling lead desertgem. Couple of others suggest that it's likely to be arsenic. I doubt it's nickel either Christian and Mackwork. Handled a fair number of pure nickel coins as well. Nevertheless, it's interesting. The coin that I'm handling is an ancient Chinese spade coin. Cast about 2000 years ago. Will post pictures later. Part of my hands feel a bit tinglish after handling. Maybe a field that I shouldn't have gone into???
I've had the same problem. I primarily collect lead coins, so I try to take the basic precautions after handling them - washing my hands and avoiding licking my fingers. I can have severe dermal reactions to nickel and, to a lesser extent copper, if I'm in continuous contact with the metal. I have a few minor problems if I've been handling cruddy bulk lots of uncleaned ancients as well.
Arsenic is sometimes used in lead alloys for tensile strength purposely, and as nonpurposely a 'come along' extraction in the mines. I ancient times, it was probably not considered, but not we know that some ( not most) people are hypersensitive to even microscopic amounts. The first time people contact poison ivy's urushiol, they may have not immediate reaction, but their immune system prepares for the following contacts and react stronger each time. Trace metals could produce a similar scenario, so it could be other metals or material ( oils, acids, and other chemicals) the ancients coins might have been cleaned with.
