Good morning. I just bought a BUNCH (around 200) old world coins from a collection that ended around 1948. Many are 1700's 1800's, some are ancient. Many appear uncirculated. I believe this collection, as such, had only one owner-- I have good reason to believe this. I don't know how these coins were handled by the original owner, but I know they had at least some handling recently with bare fingers to get them in and out of the manila coin packets, photograph them for auction, etc. I would like to clean these coins, to at least eliminate the possible fingerprints of the auction house employees. What do y'all suggest? Just mild soap and water? Thanks.
Hello, I would not attempt to monkey with them any further. At this point whatever damage that was done is done and all you could do is more damage. For ancients, many have been cleaned already and there's a little more foregiveness for them but it doesn't mean people want them cleaned further if not really necesssary. Collectors value original surfaces and once something that has never been cleaned is cleaned, there's no going back. Some things had to be cleaned, some do not. It used to be an acceptable practice within the hobby ages ago, but is not anymore. Anyone who deals with coins at a reputable auction house would know enough to handle them by the edges only. If someone didn't, it is what it is now. Sometimes fingerprints will show up decades later.
Unfortunately, not much can be done. A rinse in acetone is harmless to nearly all coin metals, and it would remove possible (new) fingerprints. Won't remove toning. But it will remove the light original skin on the coin that most collectors look for when buying. Some pics would be helpful.
Hadn't thought about pics. Here are the ones I bought specifically. There are hundreds where I bought the remainders in a case.
With a collection of that age, I'd be more concerned about environmental contaminants.... was the owner a smoker? Also, that plastic used was probably not museum quality. I see at least one coin in your picture with a distinct green color from PVC contamination. I highly recommend you gently and carefully rinse each coin in *pure* acetone. That will remove any fingerprint oils, as well as any environmental contaminants. For the science of what happens and instructions on how to do this... you can look at an article I wrote a few years back: https://boards.ngccoin.com/topic/243787-pvc-and-acetone-part-3-of-a-3-part-series-using-acetone/
The Saxon coin definitely has PVC. Unfortunately, many of the older methods of storage were detrimental to coins. Several world governments used to put coins in these flexible plastic wallets that destroyed them, especially in humid/ hot conditions. I was afraid the Saxon piece was going to be terribly pitted, but looks ok after you've cleaned it. No need to clean it, as the previous owner cleaned it well enough for a 100 years! I'll say, I like the Portuguese Guinea and the MacArthur the best out of the lot!
