I recently dug up some old coins that my parents had given me a long time ago. They were all just thrown in a box and are mostly just coins with no monetary value from various countries they've traveled to. Some of them have the green stuff on them! So, if I put them in cardboard 2x2 holders (because I want to hang on to them), is it possible for the green stuff to spread to my other coins if they're in the same box? Just wondering.
I would say yes....put them in acetone and let them sit for a few min...then put them in water (distilled....) Speedy
I don't know about the soapy...I considder Acetone a type of cleaning....but soapy water is more of a cleaning than Acetone is..... Needless to say I would mark either coin (either dipped in Acetone or Mineral Spirites and Soapy water) cleaned and lower the value. Speedy
Acetone ,rubbing alcohol on silver,or clad coins is fine, but must be neutralized,(soapy or just water),or it may start toneing, I dont use it on copper coins at all, I use mineral spirits and than a silicone base oil to the copper. To each his own......
I disagree total...I have talked to a grader at a grading Co. too and he agrees....anything that is done to the coin to change the look is cleaning...Acetone or anything else you said lowers the value and should lower the grade....they are also considdered a Body Bag coin...but then we all know that NGC and PCGS and ICG and ANACS have all slabbed cleaned coins... Now if the coin has PVC on it then I would agree that it NEEDS to be cleaned...or you won't have a coin soon....but it should still be considdered cleaned. Speedy
If you do this to a good coin (not recamended), You cannot tell a coin cleaned with Acetone,.Period.If you have coins like the fella stated he had that just need help, Mineral spirits and the rest mentioned is fine. Museums use the silicone based oils for coppers, Fact.You are mentioning coins cleaned improperly that gradeing services or any coin collecter can spot.Wizzed, dipped or other solutions can be detected right off.The prosses I mentioned will neither harm or detract the coin.
Green as in PVC damage or vertiges (i.e. copper rot) damage? There is a need to identify the type of "damage" or the procedures will be quite different. Those are two different damges. While acetone will remove almost all of the PVC damage, it cannot do anything against vertiges. But again, acetone should not be used for copper coins as it gives some odd toning effect to it. While you cannot really tell cleaned coins that were dipped in acetone, only copper and bronze seem to have some kind of aftereffect. But yes, silicon based oil might be one of the few options to preserve coppers as they get vertiges too easily.
Thanks for all of the ideas. I've got a mixed bag of coins. I would say that most are probably copper based, clad, some I don't know what they're made of like this gold colored coin I have from France. It's not PVC damage I don't believe because I didn't have them in anything before. They were just loose. So, my guess is some kind of verdigris.
No, acetone does *nothing* against verdigris as it's not organic. Verdigris is a copper corrosion and hence pointless. You probably need to scrap them off using a toothpick. It wouldn't hurt to keep them seperate from the rest of the non-corroded coins.
Denatured Alcohol will help get that off. I know from personal experience that crud will hurt a coin.
GD and others, What do you think about my original question though?... Will the verdigris on a coin in one 2x2 affect a coin in a holder next to it or even just in the same 2x2 box? Thanks.
I'm not sure but I wouldn't want to find out. Its better to be safe than sorry....BTW--if you don't take care of the verdigris it will totaly eat the coin from what I hear. Speedy
Probably not as corrosion is generally not an airborne problem. However, under no circumstances should you ever leave a coin showing signs of verdigis - or any other type of corrosion - loose in a box or other container with other coins.
Roy is right - verdigris is not airborne. But then just how tight is a 2x2 ? Can some of that verdigris get rubbed off the coin and then fall out from between the 2 pieces of cardboard ? You bet it can. And the next time you handle your coins - where might verdigris be but on the outside of the other holders in the box. And if you open any of those 2x2's - and a piece of the verdigris falls onto another coin and you don't see it ? Well I think you get the idea. If it was me - I would never store any coin with verdigris on it anywhere near the rest of my collection. It's just not worth the risk.
I've removed verdigris from a few low value circulated copper coins with light strokes with a soft toothbrush. It did not leave any marks visible with even low powered magnification, so maybe copper is hard enough to withstand this treatement. I would prefer this approach to using a fingernail or toothpick which are both harder than the bristles on the brush and could do more damage to the coin.
The greenish stains on copper coins is a combination of copper salts, the result of chemical corrosion. Copper chlorides are green and brown, depending on the oxidation state. Copper carbonate is green, and the hydroxide is blue. Copper oxides and sulfides are black. Any way you cut it, it seems to me that these copper compounds are not really part of the copper coin anymore. The copper salts are like a layer of chemical debris at that point. I don't quite understand the use of acetone, unless of course, one is trying not to remove the copper salts and oxidized base metals. If you soaked a highly corroded copper coin in plain water with a tiny bit of detergent, would not some of the corrosion flake off? I'll bet a sonic cleaner would raise hell with copper oxidation products. What is the difference between a copper coin that was cleaned in 1400 AD, and another cleaned in 1998? One treatment is acceptable, the other not? Signed, Ignorant, and Clearly Not Worthy of Life :thumb:
