I've asked the question on another thread, but I forgot to subscribe and can't remember which one it was. I have a bunch of roman digs that I'm trying to identify. Since most are slugs, they don't really have value, so I've decided to clean. I've never heard of hydrogen peroxide (H2O2) cleaning. How does this work, and what type of coins does this work best on? My year old experiment has ended. I took 10 unidentifiable ancients that were encrusted with vertigree and other encrustation and put them in a glass bowl and covered them with olive oil. Every other month, I took a cotton swab and rubbed over the faces. Well, after a year, the olive oil was a deep green (all the copper vertigree)...and lots of ants....well, a lot of coins are now identifiable to a certain degree but they still need a little harsher cleaning...however right now none look harshly cleaned. So far, here's what I can best determine....(the coins were bought with little or no hope of identification because of the wear and crust) BTW: Olive Oil does nothing to silver.... 1. Byzantine copper Follis(???), Front has two seated men (Jesus and king?). On the left some letters....IKO, and on the right ...vsp?The detail of the seated men is pretty clear...The rev has a big "M" with Anno on left, and the romman numerals "II" on the right. Theres a good chance this can be attributed with some work. 2. Roman provincial copper. Between the size of a quarter and half. Young Roman empror facing right with radiant head. The reverse has another head facing right. Looks female, and smaller then the ceasar. Has some sort of tiera? Its not the Greek version...Theres little hope for this one since the back is almost shaved. When the oil was removed, I thought there was a counterstamp on the back, but I need a magnifying glass; however, I think its just bad corrosion. 3. Quarter sized Greek Copper. Beautiful high relief portrait of a lady facing right. Her hair is pulled in a bun. The portrait is circled by little dots...the back is the typical Zeus sitting . It appears he's holding Nike? (small winged angel?). A few letters might be able to be made out. 4. AE3/4 Constitine. He's facing right, and has a small headband. Some lighter color vertigree still exists, but the eye and "crown" detail is pretty clear. The reverse has a wreath, and letters inside. With a little more cleaning, it might be able to be made out. 5. Roman AE4. Again, I would think Constitine; however, its a little too round. Some letters might be made out with a little thought and cleaning. The Reverse has to soldiers with standards. However, the back can't be read anymore. 6. An irregular shapped Byzantine half follis. Front has a Roman Emperor figure facing right (annastasias?). The letters ANYSPPSV are clearly visible. The back has a beautifully (although partial "K", with something that looks like a Mason's compas to the right. Definitely researchable. 7. Small Greek copper coin. I had hopes for this one, but the cleaning actually took away some of the design. The front appears to look like a femal looking right. I'm not working on this one. 8. Small ALexander 1/2 disme size. Alexander is facing right and he appears to have a lions main...the back has a figure...lOL its either a charging bull to the right (horns down) or a bumble bee flying...possibilites.... 9. A Byzantine follis. Same size as #1. Obv..Two people standing holding a cross between them. It appears one is the Virgin Mary, the other????The rev has an image of Christ. No letters are visible. Similar to http://cgi.ebay.com/1152-AD-Byzanti...28QQihZ012QQcategoryZ3364QQrdZ1QQcmdZViewItem 10. A greek quarter sized copper. Tyche? facing right. Rev. Athena facing left, had outstreached, with shild on the ground leaning up against her left leg. No letters are visible. So, the research is a labor of love. Nobody would be interested in the pieces because of their condition, but it sure is fun. Now I have to dig out my books.....
Well, I know nothing of olive oil and coins or even hydrogen peroxide and coins. but silver and hydrogen peroxide -- well, I hope you're only using the standard 3% you get at a drug store (97% water). silver and hydrogen peroxide mixed together can make a nice rocket engine -- but it's not nice to the silver. see also http://science.howstuffworks.com/question159.htm
With H2O2 remember the worst thing you can do with copper is expose it to Oxygen. What you think is Vertigris is in reality usually Copper Carbonate [CuCO3-Cu(OH)2].
Of course but you will not usually get this from a coin just being exposed to air. Usually copper Acetate is derived from exposure to many differnt Acetate products. Copper coins develope reddening and then a green patina from normal exposure to air.
