This coin had the absolute most encrustation I've ever seen in my life. This wasn't even dirt or rock; it was multiple layers of the most intense oxdiation - copper, iron, and probably a few other oxides deposited on the entire surface of the coin. There was enough evidence of silver that i knew this could be good, and I was pretty sure I saw a "PVS" on the legend, indicating a Philip the Arab. It is broken, but its kinda neat because it allows me a glimpse into the (good) silver core. After soaking in Sodium Hydroxide for around 24 hours, it still had major iron oxide deposits remaining. It looked alright, but I wanted more Finally, after soaking in Sodium Thiosulfate overnight, 99% of all the deposits were removed. Now, the coin looks pretty decent. The main downside of the Thiosulfate is that it gives the silver a rather dull gray appearance; however I prefer this to a coin covered in horn silver and oxide deposits.
Wow, @hotwheelsearl, you're giving the phrase, 'Better living through chemistry' new dimensions of meaning! Very impressive work.
Thanks! Since it was a broken, common coin, I suspect many would have tossed it in the junk pile. I couldn't stand to see it die such a sad death, so now I'm the proud owner of half an antoninianus (does that mean I have one denarius now?)
...Hang on, from my antiquated edition of Sear (1974), it Looks like the 'ROMAE AETERNAE' reverse, commemorating the first millenium of Rome. Can't think of a better reverse for him.
No, unfortunately. Do you have any idea what denarii of Philip bring in the market? Neither do I. I don't have an acsearch membership. https://www.acsearch.info/search.ht...s=1&thesaurus=1&order=0¤cy=usd&company= IMHO you did wonderfully with that broken coin. What you learned from cleaning it could be put to use by many here on coins that were whole. Is there another 'drug' you could give to Philip that might improve the dull gray? Ammonia? Peroxide? Bicarb? Lemon juice? If he participates in every drug trial he might get cured.....or dissolve???
Haha, those actual denarii are wonderfully rare and expensive, and I never expect to be able to afford one... I'll settle for 1/2 ant, a "nominal denarius," if you will... Thanks for your kind comment! I certainly learned an interesting facet of chemicals: For some reason, Sodium Hydroxide does not entirely remove either a) horn silver or b) iron oxide. This is strange, since NaOh is PH 13, while Sodium Thiosulfate is PH 7-9. Why would a harsher base have less of an impact on certain deposits than a milder base? Another thing I've found, which may come in handy for brightening up the coin: every silver coin I've tossed in hydroxide comes out rather shiny silver, while every silver coin in thiosulfate comes out gray and dull. I can probably dunk this one into hydroxide for a short time (10 minutes?) and potentially recover some of the shininess. Also, I've learned that prolonged exposure to these chemicals actually will erode away details, sometimes considerably. If a coin had a weak strike to begin with, it could almost erode the details all the way off!
One reason might be to learn the lesson that it was a mistake to brighten it without making that discovery on a 'good' coin. The hardest part of coin cleaning is to know when to stop and leave well enough alone. There is also the matter of opinions. While I might prefer gray, there are many people who seem to expect their 2000 year old ancient to shine like a new penny. It is hard for those of one type to see the other view without saying that you are ruining the coin. Today, there are certain dealers who seem to specialize in fully, brightly cleaned coins. My collection has both types since not all coins I want are available in multiple copies at any given time. I tend to avoid certain 'looks' that bother me (e.g. I really do not like the Hermanubis collection surfaces) but, overall, color means less to me that the lack of polishing scratches or incrustations that make it hard to read the legends.
