Cleaning Ancients without Destroying Them

I was curious if anybody has some suggestions on how to clean crusty roman coins. I searched the Internet and found various ways of using olive oil to clean them up. Soaking them for up to several months in an olive oil bath and then using a dental pick to carefully remove the debris.

I tried this and I was dissatisfied with the results, sometimes it worked, sometimes it didn't. Sometimes they are just so crusty that the debris of the ages is just too tough to remove.

Another method is the olive oil hot-pot, requiring you to heat up the coins in olive oil on the stove and add a little lemon juice. I have not tried this method yet.

Lastly there is the suggestion to use liquid descaler for about 24 hours of immersion time and then wash the coins with distilled water. I found this method to be somewhat destructive and sometimes obliterated portraits and legends, as well as reverses.

So I am basically unimpressed with these methodologies and have decided for the time being to forgo efforts to clean them up. Sometimes it appears that the best thing to do with these crusties is simply to attribute them without attempts to clean, leaving the residue of the ages intact.

 

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There used be to a couple chat groups dedicated to cleaning ancients. You generally outlined the main methods. I preferred soaking in distilled water for about a week, brushing with stiff nylon bristled brush, change the water and repeat (for months) with an occasional workout with dental picks. Some people prefer pin vises or rose thorns instead of dental tools. I was never convinced that olive oil was any better than distilled water and it was a lot messier.

Electrolysis works in some cases but you have to be careful or you'll completely ruin the coin.

The level of success depends on the coin and the encrustation. No single technique works on everything and you may find that under the crust, the coin is too corroded to ID

 

I agree with this entire post but especially like the water over oil. Olive oil is for salads but only in moderation.

 

I didn't seem to have any real noticeable improvement with using olive oil vs. water either (I soaked some for nearly a year).

 

I tried my hand at cleaning Ancients, but gave up in the long run. I used both methods (distilled water vs olive oil), but preferred the water. The olive oil seemed to darken the coins too much. The biggest reason I gave up was the poor quality of coins. Most were not worth my effort, but even those that came out okay, were not worth the initial investment. There is no way anyone is selling unclean lots without first going through them for anything of value. I wish you, and other coin cleaners, the best of luck however.

 

I am a dealer and I dont clean coins. That doesn't mean dealers dont clean coins, many of them do. I have always wondered about the olive oil concept. Seems like a coin geek urban legend. While olive oil is mildly acidic it really wont do much if anything at all, and results depend entirely upon the metal composition and the type of encrustations.

I'll give out one 'secret' of the hobby: While most of us are aware that nearly all ancient coins have been cleaned what many dont realize is that the cleaning is almost entirely accomplished with chemicals. Sorry to burst bubbles, but that is the truth of the matter.

Now, I dont recommend that anyone clean coins. If one wishes to do so, seek appropriate counsel but be forewarned, cleaning methods are very closely guarded and you wont likely get anyone to open up as to how to do it.

So, my advice is to only buy coins in which you are pleased with. Forget the uncleaned junk. There isn't anything there anyway.

 

This is the best advice of all!

 

That should be a quote pasted onto all ancient coin forums.

 

I purchased a bulk lot of lightly cleaned Judaean coins. They were rather gritty to the touch so I soaked them in distilled water in a Pyrex glass bowl for three weeks. I changed the water every three days. Other than some of the grit settling to the bottom of the bowl I can’t say that there was any visible change. I’m sure however that the process removed more grit than was obvious.

 

I had recently tried cleaning a crusty Roman coin with just distilled water and brush. The biggest key to cleaning coins is patience imo, which I don't have.... so I gave the coin to a friends son a couple days ago lol

 

A lot depends on the encrustation type, I had this Tiberius As, with green stuff all over the Altar, so I soaked in distilled water with half a teaspoon of soda-ash 2-3 weeks, watching the water going a greeny-blue and scrubbing with a nylon brush. Below is before, and next two results.

 

Thanks Doug. I picked up most of my information from people like you 15+ years ago. Got tired of cleaning and rarely finding anything good, but by doing so, I learned a lot about ancients and was able to put together a nice library. I'm off to other collecting interests, but am glad that I picked up the knowledge and really do cherish the books

 

There is no easy way to do it.

To get good quality uncleaned coins nowadays you have to pay the same price as you would for clean coins.

Now 30 years ago it was different but most of those stocks I know about have been used up years ago.

 

One of the questions too is where do these bulk coins come from, assuming they have not been in collector's hands, sometimes you get vague information about a middle eastern, balkan, or british origin. I assume by guys with metal detectors. Some of them are so crusty that they must have been exposed to groundwater as they sat in a ground or a pot somewhere.

 

If they are late Roman high probability they are Balkan, and not provenanced. I found a modern Bulgarian coin in a lot once, which does not prove those came from there, but the seller also claimed that is where they came from. As of last year it is illegal to export newly found antiquities from Israel, and dealers are only allowed to sell their existing inventory.
Soil also can corrode and those affected would be sold off because it would be too time consuming to clean them. The better coins from the same hoard would be sold to others higher in the food chain.

 

I have a passing interest in ancients (I am fickle) and when I first started with them a couple of years ago, I ordered uncleaned lots 3X and tried lots of cleaning methods. The best I found was soaking in soapy water for months, changing the water occasionally and brushing the coins with a toothbrush you have cut the bristles to half length to increase the stiffness. A copper/brass brush can also work for the more stubborn encrustations. Before giving up, give them a couple of nice clean water rinses followed by a couple of distilled water rinses.

 

Actually the altar looks a bit better when cleaned, more detail. I had some success with 4th century bronze pieces with layers of crud - some of the GLORIA EXERCITVS pieces of Constantine II, Constans, and Constantius II where the reverses cleaned up nicely. I used the olive oil treatment followed by careful scraping with a dental pick, but I agree with @Bing that the coins seemed to darken and take on a brown coloration, not totally desirable. And an AE1 of Jovian, which was encrusted with green crud. I elected not to clean an AE1 of Julian with the Apis bull on the reverse, about F condition. Kind of a nice coin without cleaning. My days of buying uncleaned hoards might be over.

 

There is also a difference between buying "uncleaned" ancients (dirtballs) and some ancients that look like they might be improved with some judicious cleaning.

 

I began by buying uncleaned lots from ebay. I would say that I would be lucky to find one decent coin in about 50.

There are no shortcuts to cleaning. Patience is your friend. I don't like olive oil. It darkens the patina and is gunky. Distilled water or de-ionised water is the best bet. Leave to soak. Leave the container somewhere handy where you can give it a shake once or twice, or thrice a day. Change the water when it becomes cloudy. Brush every few days. Some encrustations will take months and months to "soften". Stay away from sharp implements if you are not experienced. Brass brushes WILL damage the patina. Electrolysis kits belong in the bin.

Cleaning to begin with is a great education.

 

I have to add that not all "patinas" are desirable.