Although the general wisdom is you don’t clean coins (although I sometimes do anyway, which I will cover in a future post), cleaning Roman coins is actually a hobby in and of itself, and its one of the first things I got into when I dived down the numismatic rabbit hole.
Step One: Get Some Coins
I’ve gotten most of my dirty coins from eBay. Search for “uncleaned Roman coins” and you’ll get a couple hundred results. Things to consider when evaluating listings:
- Most display an image of a pile of dirty coins. That does not mean you’re buying the entire pile. Frequently the price is PER COIN. This is mentioned in the listing, but I’m highlighting it regardless.
- Look at the pictures. While, yes, these coins are dirty, if all the coins in the picture are just flat, featureless disks, I fear there may not be much left under the dirt (although I’ve never purchased coins from such listings.)
- Some sales flat out say their coins are in “poor condition.” I suspect they’re so poor as to not be fun, but, again, I’ve never purchased them.
- “Culls” are coins in very poor condition.
- Ignore it when sellers say their coins are “very rare.” They’re not.
- Coins will almost assuredly be from the 4th century, regardless what span of dates the sellers claim.
- Some sellers will describe their coins as AE1, 2, 3, or 4. AE3 coins are 17-21mm, which is comparable in size to American dimes, pennies and nickels. AE4s are smaller, and I’m not a fan of them. You’re not likely to see A1s advertised, although there might be some AE2s, which are comparable to nickels and quarters. I aim for AE3s.
My favorite dealer is ivlla because I always get some good coins from their lots and they show the specific coins for sale. If it’s ten coins, the picture will be of the ten coins you’re going to get. Unfortunately, at the time of this posting, the store is closed due to the owner having had a stroke. I mention it here in the hopes the store will open in the future.
You can also go to Dirty Old Coins, which sells coins individually.
I strongly suggest buying more than one (regardless of seller). Some coins will suck. You’ll clean them off and find they really are just lumpy bronze disks. Buying several will greatly improve your chances of enjoying coin cleaning.
Step Two: Rinse the Coins
The first thing I do is soak all the coins in water and a mild dish soap like Palmolive.
Step Three: Use a Soft Brass Brush
After the soak, I brush coins with a soft brass jewelry brush. You can get them in various places online for less than $10, like this soft brass brush on Amazon. The key word is “soft.” Don’t use brass brushes made for automotive cleaning. They are far too hard and can scratch the coin.
Step Four: Rinse and Repeat, Literally
Mix up a batch of fresh water and dish soap, then soak the coins for at least a day. Then brush them again. You may have to do this multiple times.
If the coins have a lot of gunk on them, you might soak them in olive oil. I’ve been told non-virginal is actually better than virginal, although I don’t know why. Basically, buy whatever is cheapest.
Some people soak really encrusted coins for months. I don’t have the patience. If it takes that long, I presume they’re never going to get clean and abandon them.
Step Five: Toothbrush Brushing
At some point, I switch to a toothbrush for brushing. The softer bristles can get into the crevices now that the surface dirt has been cleaned off.
Step Six: Are They Clean Yet?
After brushing and rinsing, I wipe the coins with a paper towel. If the towel comes away clean or nearly clean, they’re ready for the next step. Otherwise, it’s more soaking and brushing.
Step Seven: Picking at the Details
There are a variety of items marketed as coin cleaning tools, but I mostly use a dental pick I picked up at Walgreens. I also have a magnifying visor so I can see the details hands-free.
Website after website warns you to be careful you don’t pick off the patina. These coins are bronze, which looks similar to copper. Over the years, the bronze has oxidized, forming a patina. Most commonly, the patinas are green or brown, but it depends on the coin’s environment. Without a patina, the coin would corrode into nothing.
However, with experience, I’ve realized that I’ve been so careful about not damaging the patina that I haven’t been getting all the dirt off. Patinas are much tougher than I expected, and dirt is far more stubborn. You do, in fact, have to use a fair bit of pressure to get all the dirt out, and I’ve only picked off the patina a couple times.
I’ll address identifying coins in a future post.