Posted 06/19/2022 11:44 pm
It all depends on what you mean by "dirt".
- Actual dirt, or other physical debris? Sure, scrape it off if you like. A coin that's built up that much dirt and debris is likely to already be heavily worn, so we're not talking about a high-grade rarity. But I would recommend using something made of wood or plastic, rather than metal - a rose-thorn-on-a-stick is a standard dirt-removal tool for ancient and mediaeval coins that are dug up out of the ground. Though frankly, for dirt, a good old soak in soapy water and a rinse in pure water is probably good enough to help.
- Oxidation and tarnish? DO NOT remove. This is part of the coin's "natural surface" now; cleaning it, especially on a worn coin, simply makes the coin look flat and un-natural.
- Corrosion by-products? It would be unusual for the edge of a coin to be corroded and the front and back faces to still be fine, but I have occasionally seen it. The coin is already "ruined" by corrosion; cleaning it isn't going to make things much worse.
As a general rule, people don't bother with cleaning the edge of a coin, because it's a lot of work for something that impacts the coin's appearance very little. Indeed, the standard recommendation when experimenting with coin cleaning is if you have a new solution or reagent you are testing on a coin, test it on the coin's edge first, because people care far less about funny staining on a coin when it's on the edge.
- Actual dirt, or other physical debris? Sure, scrape it off if you like. A coin that's built up that much dirt and debris is likely to already be heavily worn, so we're not talking about a high-grade rarity. But I would recommend using something made of wood or plastic, rather than metal - a rose-thorn-on-a-stick is a standard dirt-removal tool for ancient and mediaeval coins that are dug up out of the ground. Though frankly, for dirt, a good old soak in soapy water and a rinse in pure water is probably good enough to help.
- Oxidation and tarnish? DO NOT remove. This is part of the coin's "natural surface" now; cleaning it, especially on a worn coin, simply makes the coin look flat and un-natural.
- Corrosion by-products? It would be unusual for the edge of a coin to be corroded and the front and back faces to still be fine, but I have occasionally seen it. The coin is already "ruined" by corrosion; cleaning it isn't going to make things much worse.
As a general rule, people don't bother with cleaning the edge of a coin, because it's a lot of work for something that impacts the coin's appearance very little. Indeed, the standard recommendation when experimenting with coin cleaning is if you have a new solution or reagent you are testing on a coin, test it on the coin's edge first, because people care far less about funny staining on a coin when it's on the edge.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
