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Best way to remove "green death"?

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I have fairly inexpensive bronze cent I want to remove green death from. What is my best option?

 

1. Soak in olive oil for ___ weeks and remove with toothpick.

 

2. Soak in mineral oil for ___ weeks and remove with toothpick.

 

3. Dab on MS70, remove with toothpick.

 

4. Something else (please explain).

 

It appears anything I do will mess with the coin in one way or another, but I don't want to let it sit as it is and watch the green death grow.

 

Copper experts, please advise.

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True but the olive oil is also slightly acidic which makes it work a little faster. Mineral oil will soften but does nothing to promote the breakdown of the corrosion. On the other hand the slight acidity of the olive oil can eventually change the color of the copper.

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How long should it be soaked in olive oil to loosen the grime but not change the color of the copper?

 

I've read elsewhere that a toothpick is too soft and that I should use a rose thorn instead.

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How long should it be soaked in olive oil to loosen the grime but not change the color of the copper?

Good question. Answer, until the color starts to turn. There is to way to give a definite answer because it will vary depending on the acidity of the oil and how heavy the patina is on the coin.

 

The rose thornhas a couple of advantages. It is denser and won't soa up th oil and get soft as readily and thetoothpick will. It also comes to a much finer point which is good for getting into smaller tighter places.

 

I do need to clarify something here. When you said "Green Death" I assumed you were referring to verdigris corrosion. If you mean the green slime of PVC contamination that is a different matter altogether.

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I have cleaned copper with "green death" with some success(unless deeply pitted into surface). I have found soaking for 6 months in Extra Virgin Olive Oil and limited cleaning monthly with a thorn( apple is what I used). Do not dig, just lightly pick at the verdigris. This will allow the olive oil a little help in going deeper a little faster. I did this first with a Lincoln cent that was unreadable and which became a 1911 S which at the time was worth about $3 in Good. I then moved onto an 1802 Draped Bust Large Cent which elevated it to a VG/Fine coin(my opinion). I then cleaned an 1806 Half dime which came out very nice-so much so I was able to get a grade by sending it to NCS(which did very little to improve coin's overall look), this gave it a details grade of Fine. So yes, it can be done with limited success, but just do not expect too much, only improvement, not complete restoration. Wish I had taken before and after pics but never occurred to me at the time.

Good luck

Jim

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I do need to clarify something here. When you said "Green Death" I assumed you were referring to verdigris corrosion.

 

That's exactly what I mean.

 

It appears my wife threw out the bottle of regular olive oil I'd placed in the guest bathroom (she probably wondered what it was for). Since I didn't have anything else handy I put it in a jar and added mineral oil. I'll put a rose thorn to work and pick at the grime little by little as the oil loosens it up. Fortunately the coin is a Straits Settlements cent that is square, so it will be easier to hold it in place as I look at it through a loupe with one hand and dig at the grime with the other.

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For lower grade, circulated stuff, I've had suprisingly good results with a product called Goo-Gone. It does not discolor coins, and does nto affect toning - just gunk (both PVC green and green crud that grows on copper). If the coin is pitted or the green grunk is really imbedded, it will not "fix" it. If it is limited to the surface, it will come off. I use a tooth pick or a Q-Tip to gently remove crustrations, and then do a final rinse in DI water.

 

Hope this helps-

 

 

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To remove hard and crusted verdigris, 10K acid solution( nitric acid) works very well. Place a small amount on a Q-tip and dab at the verdigris site. The solution works in a couple of seconds. You will discolor that particular area, so you may want to completely wipe the entire coin. Rinse quickly with water. The entire surface will be freshly exposed copper and over time will tone down.

 

 

TRUTH

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For lower grade, circulated stuff, I've had suprisingly good results with a product called Goo-Gone. It does not discolor coins, and does nto affect toning - just gunk (both PVC green and green crud that grows on copper). If the coin is pitted or the green grunk is really imbedded, it will not "fix" it. If it is limited to the surface, it will come off. I use a tooth pick or a Q-Tip to gently remove crustrations, and then do a final rinse in DI water.

 

Hope this helps-

 

 

Interesting. Thanks for the tip and welcome to the boards! :acclaim:

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To remove hard and crusted verdigris, 10K acid solution( nitric acid) works very well. Place a small amount on a Q-tip and dab at the verdigris site. The solution works in a couple of seconds. You will discolor that particular area, so you may want to completely wipe the entire coin. Rinse quickly with water. The entire surface will be freshly exposed copper and over time will tone down.

TRUTH

 

The coin is probably MS63 BN, and I'd feel really weird about using any kind of acidic solution stronger than olive oil on it. I'm afraid it might affect the satiny luster it has under the patina.

 

A dealer told me to use a particular brand of "Sudsy Ammonia" to clean off green death from an old medal I had, and it basically worked as a dip. The raw copper color didn't look so good. doh!

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The coin is probably MS63 BN, and I'd feel really weird about using any kind of acidic solution stronger than olive oil on it. I'm afraid it might affect the satiny luster it has under the patina.

Don't just be afraid, I guarantee it will. You would lucky to have any luster left.

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The coin is probably MS63 BN, and I'd feel really weird about using any kind of acidic solution stronger than olive oil on it. I'm afraid it might affect the satiny luster it has under the patina.

Don't just be afraid, I guarantee it will. You would lucky to have any luster left.

 

Not correct. The 10K solution is diluted enough to allow remaining luster to remain. However, the imperfections under the patina will become evident. A nitric acid solution of 12K or above is too strong. The key to verdigis removal is to allow the acid to react on that portion of the coin, then rinse away. Then the acid is applied to the entire surface to match the existing spot. This works well with nickel coins also. It is not recommended for silver coinage, since the applied areas will create a dull or stained surface which cannot be removed.

 

 

 

TRUTH

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I soaked the coin for 5 weeks in mineral oil and tried to pick the green death off with a rose thorn. I don't think any of it came off. Now I have it in extra virgin olive oil, and I'll see if it will soften it up in the next few weeks.

 

If that doesn't work I'll look into the 10K solution.

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I remember reading something about using a soak and then periodically changing the soak and adding something to the old soak to chemically test whether it was still making progress removing the corrosion.

 

It's in one of Sayles' ancient coin collecting books.

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Found it. -- Ancient Coin Collecting by Wayne G. Sayles

 

First, just to make sure of which situation we're dealing with, the book talks about two types of bronze corrosion issues.

 

1. Verdigris (hard green encrustations)

 

In those cases he advises to use a magnifier, cut a piece of bamboo to have a sharp edge and mechanically try to lift the corrosion off with the edge. He also advises to stay away from monocular magnification as you can't judge the depth well enough to avoid scratching.

 

If they adhere too tightly to pry off, he suggests softening it for later prying with a q-tip with "commercial bathroom cleaners designed to remove lime". If none of that works, then acid bath / dip / stripping is the next step.

 

2. Bronze disease (light green powder on the coin often in pits)

 

This is the one I was remembering. He says you need to remove the chlorides by soaking in de-ionized water or triple distilled HPLC grade H2O. Long soakings over months, changing the water daily. Use silver nitrate to add to old water (after the coin is removed) to look for milky coloring that shows that chlorides are still leaching out. Once the water remains clear, heat the coin in an oven at 200 to 250 degrees for a few hours (don't exceed that temperature range) to "drive out lingering gases".

 

Then coat the coin in renaissance wax or acrylic floor wax to keep air and moisture out and prevent recurrence.

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Saw somebody else say:

 

oil soak bath (good quality oil) -- stick it in a potato -- back to bath -- back to potato -- etc.

 

Tooth pick or sliced bamboo in between.

 

No idea if this works. Although I did once clean an 1879 german mark with a potato and it worked alright.

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Found it. -- Ancient Coin Collecting by Wayne G. Sayles

2. Bronze disease (light green powder on the coin often in pits)

 

This is the one I was remembering. He says you need to remove the chlorides by soaking in de-ionized water or triple distilled HPLC grade H2O. Long soakings over months, changing the water daily. Use silver nitrate to add to old water (after the coin is removed) to look for milky coloring that shows that chlorides are still leaching out. Once the water remains clear, heat the coin in an oven at 200 to 250 degrees for a few hours (don't exceed that temperature range) to "drive out lingering gases".

 

Then coat the coin in renaissance wax or acrylic floor wax to keep air and moisture out and prevent recurrence.

 

My coin had "bronze disease". I didn't try the de-ionized water as recommended by Sayles, but instead I took the easy way. I soaked the coin in extra virgin olive oil for 6 weeks and took a rose thorn to the infected letters on the coin. Before I even got to work on it, I saw green coming off the coin and sticking to the paper towel. After I was done I noticed some areas that were covered in green were darker than the rest of the coin, so I put it back into new EVOO for another short soak. Once it's out I'll rinse it in filtered water, soak in acetone, and let dry.

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is extra virgin oil the best or is mineral oil ok to use on metals also?

 

Some forum members claim mineral oil is better since it doesn't turn racid like olive oil. I've never used either since I don't collect copper.

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is extra virgin oil the best or is mineral oil ok to use on metals also?

 

Some forum members claim mineral oil is better since it doesn't turn racid like olive oil. I've never used either since I don't collect copper.

 

The problem I had with mineral oil is that it didn't do anything at all. I've heard it prevents the growth of green death, but it didn't do diddly in its removal.

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