Crustys or Uncleaned Ancient Coins, Can be very fragile. Cleaning these coins requires skill, experience, and patience. Please read this guide before your coins are nothing more than metal slabs!
Cleaning "Crusty's" aka Uncleaned Ancient Coins.
One thing to keep in mind is that these thin coins have been buried in dirt for over a thousand years and may be very fragile. I recommend attempting the softest cleaning techniques before you attack your coins with a dremel or resort to electro shock therapy. ( seriously people do it!) As a newbie to cleaning crusty's, I had ordered an electrolysis gadget from eBay (which turned out to be nothing more than a cell phone charger that had been cut and connected to two alligator clips along with a metal rod) it claimed to clean ancient coins/artifacts and make them look almost new again. Well the first coin I tried with this gizmo ended up broken in about four different pieces... You get the idea. Anyways enough about my failures, let's get back to some proven methods of cleaning coins. The first thing you should step is just rinsing the coins under low pressure water, gently brushing them with a soft bristled toothbrush if needed. This methods is surprisingly effective. If this fails then your next best option would be to soak the troublesome coins in olive oil. The down side is this process can take up to two weeks to fully work, but more often than not coins will come clean very easily after this with just a light brushing. I realize it may be hard to patiently wait for two weeks but the wait is worth it. Whatever you do please don't try quicker, harsh alternatives in hopes of speeding the cleaning up. Doing so you risk damaging or breaking your coins. Now if you have soaked and scrubbed until you can scrub no more. Then it might be time to resort to an ultra sonic cleaner. These are normally used for cleaning jewelry. An ultra sonic machine works by submersing your coins in water (and usually done kind of cleaning solution) while ultra sonic waves pulse through them, theoretically breaking up dirt andgrime your coins shiny and clean. I have tried this technique but saw no visible results. However it may have been due to operator error and I just didn't use the machine correctly. Ultra sonic cleaners can be found in the jewellery section of most department stores for around $30.00. Now your coin still isn't clean? You could try different chemicals and cleaners offered on various websites that claim to work miracles. Or you could try a dremel, or maybe electro shock. By my advice at this point would be to just moved on and get s new coin to clean. This is supposed to be fun. The moment it becomes work is when its time to call it quits.