Cleaning of ancient coins - Help

[Franco S]

Several years ago I bought about a dozen of ancient coins, roman, Greek or byzantine. Not sure exactly.  They were very dirty and soiled. I was told to dip them in olive oil and let them soak as long as I could. So I did. Not being in a hurry I let them in all these years. Not sure if this is good or not but well I took the as long as you can let them soak in the better was the right thing. Well today I found my treasure still soaked in the virgin olive oil but now the oil got a bit ticker and gummy. I decided to remove the coins and start to clean them with soap water. Some are looking good some other are still dark and can feel the dirt somehow hard. Is what I did wrong? Or? and now that I did it is there something better that I can do to make the rest most hard to look good? Any suggestion would be greatly appreciated. Thanks

[peterpil19]

Hi Franco,

Welcome to the discussion board!

It does not sound like you did anything wrong. Read this: Uncleaned Coins Not For Profit.

Cleaning coins is a time-consuming process and may involve multiple soaks over long periods of time. When you take them out you need to use something to scrub them with and remove the dirt. I use a toothbrush on which I have cut the bristles right down. For detailed work I use toothpicks or something similarly sharp and unlikely to ruin the patina on the coin. Years ago I used to use a diamond dusted toothpick. Once I have done all I can, if the dirt is still stubborn, they go back in for another soak (fresh olive oil, if you use that, I prefer distilled water).

For really stubborn coins there are different techniques which may be employed but they are harsher and could result in irreversible damage to the patina and the coin.

There are plenty of others here who are many orders more experienced than I am on this subject. Perhaps post some photos of the coins you are having particular difficulty with and they will jump in to lend their expertise.

Peter

[Dk0311USMC]

I started out my collecting by cleaning a lot of coins and attributing them. I had tried just about every method in the book and eventually found that I got the most success from distilled water.  Instead of letting coins sit forever and ever in a solution, I would regularly change out some Tupperware with fresh distilled water and a few coins in them.  Letting osmosis do its trick, I would give each one a good scrubbing every few days or week and a good wipe/rinse, then back in a fresh bit of distilled water again.  After a while of soft bristled toothbrushes not doing a great job, I went into a bass pro shop and bought a stiff nylon bristled brush for gun cleaning to use on the coins.  Eventually I ordered a brass brush as well for stubborn encrustations.  Learning which coins to use soft bushes on and which ones you can go ahead and get away with a brass brush takes some finesse and time. Some patinas are soft and others are pretty solid and can handle a little brushing of a brass brush for stubborn crusty dirt.  Since I have gone through a whole lot of uncleaned coins and don't have as much patients as you to just let them sit, I have found my method pretty useful for cleaning and attributing coins in relatively quick fashion.  For the most part my patinas are intact still and the junk is gone. I also used an X-acto knife for precision cleaning.  It looks pretty intimidating but you can accomplish a lot around corners and crevices with the right amount of pressure applied. 

[Luke G2]

Distilled water soaks. I actually did the same thing you did. The black gunk does come off. Just do like the other posters said, soak & brush from time to time.