Thanks @furryfrog02 for a heartwarming portrait of father and son uncovering the secret of a roman emperor hidden for centuries!
You guys scrub with wire brushes? The guys on the other side of the river would have a heart attack........
Only when they are really crusty. Once most of dirt comes off we go from wire brass brushes to the nylon like my son is using.
I am an elementary science teacher. It is my professional opinion, (it's okay to laugh; I get that all the time), that your next purchase should be a stereo microscope. Nothing fancy; a simple 10x-30x power scope is all you need. Something like this: https://www.amscope.com/sharp-forward-stereo-microscope-10x-30x.html (Avoid the temptation to go for higher magnification power. They are harder to use and defeat the whole purpose of getting one for a kid.) Then go to a hobby or hardware store and get a brass rod and a sharpening stone to sharpen one of the rod ends into a point. Once you've got a coin pretty clean, put it under the scope and use the brass rod to pick any remaining dirt out of the nooks and crannies of the coins. And now here's where I admit the fundamental disingenuity of my suggestion: Yes, you son will probably enjoy cleaning coins this way. But my hope is he will also enjoy sticking his fingers under the scope and looking at them, too. And then enjoy going outside and finding bugs, rocks, plants and whatnot to look at under it, and he'll get excited about how cool everything looks under a microscope and his curiosity about the natural world will just take off. And your coins will end up cleaner, too.
Only the crustiest should receive this treatment (IMHO) and it should be done gently under a magnifier. It’s easy to over-do it and get carried away. When I was just starting out collecting ancients—I used to be into boxed sets and many of them are over-cleaned. You can actually see the scratches on the coins. I’ve replaced all of these over-cleaned Indo-Scythian drachma with higher quality specimens.
What a wonderful father-son project. When my son was little (he's now out of college), he collected Lincoln cents and statehood quarters out of pocket change. So it's not surprising -- but still funny -- that he asked me, "Did you get all these old Roman coins in your change when you were a boy, Dad?"
What an awesome hobby to share with your son! You sound like a great dad! Would you consider adopting me? My dad had no interest in history whatsoever in fact he despised anything that he thought was old and outdated. Everything in our house had to be modern.
@furryfrog02 , that is a fantastic time spending with your boy! Congrats. I have absolutely NO patience to clean coins... Unfortunately, this would be my approach: RI Postumus struck by Aureolus 268 CE Revolt of Milan Concordia JUST kidding to all the new collectors and to @dougsmit (this was actually cleaned by @YOC for me)
Smack! About wire brushes: I see no reason to use a steel-bristle brush when brass-bristle brushes are so readily available at most hardware and department stores. We geologists have a mantra: "objects scratch objects that they are harder than." (Geologists make really boring mystics.) Steel is harder than bronze and will scratch it. Brass is softer and will not. Both will scratch silver. Brass will not scratch bronze coins and can be used without damaging it in most cases, BUT brass can be harder than the surface patina on some coins and leave scratches. This is especially the case with coins with a pale, light green patina, which can often be very soft. I have damaged coins with this kind of patina using a brass-bristle before, so be very careful with this type of surface. You should be okay on most other types of surface patina, though. Of course, it never hurts to check first. Maybe lightly brush an edge or rim and check carefully for any damage before going any further with it.
I agree with gsimonel. A stereo microscope is a fun toy for boys my age and I see no reason that a right thinking young man like your son would not benefit also. There are a hundred variations and price points. Some have accessory lights and even cameras for 2D images. I so wish I had been given one when I was 7 but those were the days of cap pistols and chemistry sets. I had to by my scope for myself much later.
I use a toothpick and standard toothbrush to remove the crud, sometimes after a distilled water soak and sometimes after I have gone to the extra step to immerse the coins in olive oil for awhile. I suppose you could use a dremel as well (I know some folks do this). If anyone in the house sees me trying to clean up the coins they usually act like I am crazy for spending so much time with tiny bits of metal.
I've looked at them before. Right now, they are a bit out of our price range. We will have to stick with a loupe and a magnifying glass.