I just received this denarius of Vespasian. It was in a small group lot. I like the obverse, but the reverse has some malachite buildup that really bugs me. It's not obvious from the photo, but the reverse is much lighter than the obverse, so I assume someone has tried, unsuccessfully, to clean it before. Should I attempt to clean it or just leave it as is? The problem with Vespasian-era denarii is that they have a higher copper content that earlier denarii, so just soaking it in lemon juice is not really an option. I have some Verdi-Care. Do you think that would be worth trying? Vespasian A.D. 69-79 AR Denarius, Rome mint, A.D. 73 Obv: IMP CAES VESP AVG CEN Rev: PONTIF MAXIM – Vespasian, seated right in curule chair, holding scepter and olive branch RIC 545 19 x 17 mm, 3.3g
I should leave it alone, like it is. The malachite does not obliterate the legend or the type. It's an almost 2000 years old coin !
Verdi-Care won't do a thing to remove mineral deposits. You could try shaving them down with a dremel tool, but you need a very steady hand not to damage the coin.
@gsimonel Or, you could try using a pointy scalpel, and a low power microscope, to remove the green deposits. However, for some people, the green deposits make the coin more interesting. It shows, that the coin is extremely old. Also, you mentioned, that the coin has a high copper content. Perhaps the green deposits, are a result of the high copper content, which would be interesting. EDIT : There may be a chemical, which may remove the green deposits, without harming the silver coin, resulting in a blast white coin. I think I've seen some CoinTalk threads, about removing various types of deposits, from silver coins, using various chemicals. Was it sodium thiosulfate? I don't remember.
What I would do: Wrap the coin in aluminum foil, which has been perforated several times by a tooth pick, and soak it overnight in concentrated lemon juice. Lemon juice alone won’t do much. Repeat as necessary. Perforating the foil let’s gases out and lemon juice in.
According to the metal analysis conducted by Butcher and Ponting Vespasian's denarii have the same fineness as post reform Neronian denarii, about 80%. Denarii would be struck at this level of fineness until Domitian's reform in 82, which raised it to @ 98%. Another reform in 85 reduced it to 90%. Under the adoptive emperors beginning with Trajan there was a steady decline, reducing the fineness well below 80%! I'm not quite sure where this myth that Vespasianic denarii are less pure than other eras comes from, but it flies in the face of the available evidence! In regards to cleaning...try lemon juice or lemon juice concentrate with a toothpick. Personally, I'd leave it as is.
One of my first Vespasian denarii, purchased in the first auction, when I bought 3 group lots, has a similar "problem" Apparently somebody tried cleaning it and the general aspect looks cleaned but the green deposits remained. Partially I think. My opinion - do no try to clean yours. There are people even here on CT doing a great job in cleaning this type of deposits. But I suspect that even if you manage to remove the green deposits, the traces on the fields will still be visible, resulting spots in different color, even more distracting than the actual situation. Again, this is my personal opinion - those deposits are a sign that the coin is almost 2000 years old and even if on an older thread a member had a completely different opinion - I think it adds character to the coin.
Usually this assertion is in reference to Nero's debasement. Denarii minted right after Nero are less fine when compared to Republican denarii. That's what I meant.
