Conservation Black Spots on Bronze/Copper

Hello

I wanted to start a discussion about conserving bronze/copper coins with black spots. I see these mostly referred to as "carbon spots" but from what I understand, they are really sulfur spots. I actually don't care much what they are or how they form (except in regards to preventing them); I would love to have a thread devoted to removing them--a place where any who have attempted to remove them share their experience.

I have seen them grow and multiply. A standard way of conserving them would be really helpful and I really am astonished that no common approach seems to exist. I've spent many hours reading up on this and mostly I just see a lot of people who have thrown their hands up in the air and given up. I believe NCS will remove them for a fee. I would love to hear how people think they remove them.

The only success I have had is via mechanical means--literally scraping them away. Obviously that is a terrible way of going about it. Is there no acid or other substance that can dissolve these away (without eating away the good parts of the coin)? The EZ-est's of the world cannot touch them.

Any thoughts are appreciated.

Thanks.

 

Log in or Sign up to hide this ad.

I look forward to seeing some answers. To the best of my knowledge, they can't really be removed without otherwise damaging the coin.

 

How do you scrape off carbon spots without leaving marks?

 

Me too! Ugh they are the worst. And I forgot to mention "fly specks"--those tiny little carbon spots. I believe that's what they're called. There HAS to be a way to remove those non-mechanically. Just something that will dissolve that substance away. There must be!

 

I have tried pulling them off with packaging tape with very little success.

 

Oh I am not saying scraping leaves no evidence. It certainly does! Often I find this better than the carbon spot. I don't mind a discoloration beneath the spot--or even pitting--Just want them gone non-mechanically.

 

This is great--and what I hoped for. Even if an unsuccessful attempt, its worth hearing. One less experiment others will have to try.

 

When any of you guys figure it out, keep it to yourself as you'll become a millionaire many times over. Good Luck.

 

I guess I feel some hope that there is a way based on the understanding that NCS will conserve a coin with these spots. They have some method. Maybe it's mechanical. I can't imagine people are just paying to have them grind it away or something. I've tried everything I can think of but have a very limited imagination for this sort of thing

 

Here I found this description of NCS:

"Founded in February 2001, Numismatic Conservation Services (NCS) is devoted to expert conservation of collectible coins, tokens and medals. NCS numismatic professionals have extensive experience in coin conservation techniques and are uniquely qualified to provide expert conservation services for coins of all metals, types and eras.

NCS conservation carefully removes surface contaminants such as PVC, soils, tarnish, carbon spots, verdigris and encrustation from coins. These conservation services are designed to preserve originality, improve eye appeal and provide long-term protection.

NCS is the conservation service of choice for the ANA and PNG."

And heres a link with a fella talking about a coin he sent them that had a carbon spot removed:

https://www.cointalk.com/threads/se...cs-and-gets-improperly-cleaned-by-ngc.261040/

 

I assure you that any method NCS uses is proprietary. Most KNOWLEDGEABLE, EXPERIENCED folks can remove many types of spots chemically just as NCS does. Some spots can be removed but the surface is destroyed where the spot was.

We are wasting time posting as EACH SPOT needs to be evaluated. In 2007 I was told that the folks at NCS evaluated spots using a microscope before deciding what to do.

PS NCS does not scrape off spots!

 

That's good. If they scraped them, there would be no hope. I've seen things saying long soak in mineral oil could break some of these down without adversely affecting the rest of the surface. Have to give it a try. Supposedly takes a long time. There's so much available info on helping all other problem coins: excessive toning, verdigris, pvc, etc etc. Just feel there's got to be somethjng someone might know of to add to the public body of information. There's so much clamor about saving coins for future generations and the responsibility we have to protect these tangible pieces of our history. Well these little black Devils are the worst of the worst

 

Just leave them and preserve the coin using VeriCare OR chemically remove the spots, there your coins so what ever makes you happy! BTW Insider is 100% correct (and usually is) so feel confident in his info it’s solid. If anybody knows about coin conservation he does.
Reed.

 

I'd love to chemically remove my spots. What chemical is the question. I must admit I didn't have high expectations when I started this thread. I have read through every one I can find and really haven't seen any chemical advice. I've read some scientific papers on the subject and they talk about mechanical removal and then preserving with benzotriazole. They talk about keeping coin or artefact away from sulfur gas emitting materials like paper and rubber, etc. But NCS has a chemical means. Perhaps it is something they concocted. Perhaps not.

And regarding each spot needing to be evaluated. There are lots of spots that can be removed with EZ-est. I'd say that those coins with spots remaining after a dip in EZ-est are the ones I'm talking about. Seems to me these spots are all the same. These are the ones I speak of. They definitely vary in how deep they go and how long they've existed and how far they've spread but they seem to all be of the same nature. Anyway I do appreciate your thoughts.

Thanks

 

52sdeer, posted: "Just leave them and preserve the coin using VeriCare OR chemically remove the spots, there your coins so what ever makes you happy! BTW Insider is 100% correct (and usually is) so feel confident in his info it’s solid. If anybody knows about coin conservation he does."

Thank you for your comments Reed. I assure you and others that in the big picture, I know very little.

I wish I was a chemist. Anything I may know came from hands on experience plus information from others. I like to remind folks that "I think I know just enough to get myself into deep..."

 

If you want to minimize your years of hands on experience go ahead but some of us know better! AND you are the emoji King on this site! Lol. Reed

 

I have 1,000s of Lincoln Wheat cents and 100s that are BU. There are dozens with black spots. Black spots that EZ-est and the like will not remove. Are you saying "Most KNOWLEDGEABLE, EXPERIENCED folks can remove" these? Maybe you are talking about the occasional spot thats created from dandruff or spittle or organic material or something. Ive seen these dissolve away in EZ-est. Im talking about carbon spots. They are really sulfur spots. There are scientific studies on them. I think everyone knows what I mean. Sure some misidentify a spot here and there as a carbon spot, but these spots I speak of are common. You see them on coins in slabs. If most knowledgeable, experienced people could remove them, Im sure someone would mention how they do it on the internet.

 

I can report that soaking in evoo (extra virgin olive oil) has little or no effect on spots or stains - I've had a dozen copper small cents in a jar of oil for over a year - the oil has become greener, probably from the couple of verdigris coins, but the coins themselves are still stained and crud-encrusted - gentle toothpick rubbing has little effect - I'll let them marinate for another year, wipe them off and toss them into my miscellaneous Wheatie and Indian Head coin tubes

 

Thank you for sharing your experience. Really appreciated. Maybe the mineral oil would work better? Have read others who've had success.

And these are the spots I refer to:

https://www.researchgate.net/publication/280248053_Some_News_about_'Black_Spots'