Soaking copper in olive oil...can't find original thread

JD

Earlier I read a thread about soaking copper in olive oil (or mineral oil). Tried it last week on an 1863 copper token that had a greenish color/residu in the legend. A week later the green's gone and the luster looks better. On a second coin it removed a bit of the corrision but didn't remove the other black spots that look like the start of corrision. On a third coin, an 1863 brass (I think) token it has had no effect on removing the black tar/oil substance covering part of the coin. One out of three is better then zero...thanks for the tip.

mdwoods

I have had some dug ancients soaking for over a year. I change the oil every so often. Also, I am digging out behing my house for a patio/deck, and found and 185? Large cent (and 2 clay marbles) which is also soaking. I am going to take a picture of the dig, and the find and post them later this week. Some coins require a much longer soak than others. I am not sure it will take the black spots off of copper. Mark

1jester

Interesting idea which I've heard of only once before. Do you have any recommendations about what coins/grades to not soak? Would you soak a coin that looked uncirculated? How do you get the oil off after a long time, by rubbing with a soft cloth? What kind of cloth?

Thanks! I like the idea, as I love olive oil, especially extra virgin; it tastes great and is supposed to be very healthy. If it's good for us, maybe it's good for copper?!

clw54

Here's an ancient thread on the subject. Not much in it, though.

This one is more current, and probably the one you're interested in.

lathmach

On cruddy old copper, put them in a jar or bowl of olive oil and put in a window that gets sunshine. Leave them for about a month. Then to remove the crud, take a toothpick and chew on it til it's real nice and soft. Then work on the coin with the softened end until it's clean. Olive oil will not have any effect on stains, this is just to loosen crud.

Ray

oreville

JD: More significantly than the 1 out of 3 results is that by doing what you have done does not harm the coins. The fact that the oil (I prefer mineral oil) does not always works in fact proves its superiority in that it is not invasive to the coin metal's surface.

If it had removed the stains such action would have been essentially a "cleaning" of the coin's surface which would have probably ruined the coin and its value.

The only negative aspect of mineral and olive oil is that it can darken light brown circulated copper coins to a darket and deeper brown.

1jester

Thanks for the info, folks!! I just looked at the previous threads and other threads/websites, and got so much info that I don't know what to do with it. I'm completely new at this, but I would like to try the olive oil/mineral oil trick on a few coins. Also, I have "bronze disease" on a few coins, and now I know what to do with them. I hope I don't get slammed for AT!!

windwhispersintrees

Try this link....everything you'd want to know about cleaning old coins, typically dug from the ground:
http://www.luxefaire.com/coin.htm
Olive oil works because it is acidic....avoid using olive oil, since this leaves residue and does indeed darken a coin.
I usually use electrolysis, but it takes awhile before you know what coins are good candidates. Sometimes the corrosion you see is indeed all that is left of a coin's details. Such coins are better left alone.
Experiment on junk coins and learn what you're doing before using any method on coins you value.

1jester

Welcome, Windwhispers. Thanks for the advice. If you don't recommend olive oil, do you recommend mineral oil? Does electrolysis involve salt water? Is vinegar OK?

I'd like to bring up the topic again. I hope you experts out there can help me. Hoping to improve some coins of mine, I just set 7 coins in extra virgin olive oil: 1)1858 Flying Eagle cent, VF. 2)1870 Ceylon 1/2 cent, VF. 3)1918-S Philippines cent, VF. 4)1821 large cent, F. 5)1835 East India Co. 1/2 Anna, VF. 6)1665 Polish shilling (copper), VF. 1934 5 zloty Poland (silver), VF. All of these coins have the original patina (usually dark brown), and none have been cleaned till now. Some have a bit of black crud between the letters.

Please help me answer some questions. I appreciate any information regarding these questions and any other relevant advice you can offer.

1) Which metals are OK to put in olive oil? Copper, brass, bronze: I assume so. Is silver OK to soak? What about nickel (copper-nickel)? Aluminum?

2) During the soak, should the glass jar be in direct sunlight? Is it OK for it to be heated by the sun's rays? And should the jar be sealed (airtight)? I've heard that the oil should be changed every week or two. Is extra virgin the best?

3) How do you remove the oil after the soak? I've heard that you can use 70% rubbing alcohol. Is this safe? Won't alcohol stain the metal or damage it? I am certain that I won't use acetone on copper. (but that it's ok on silver: is this true?). If not a solvent, then what? plain water? soap and water? distilled water? What about rubbing the coin dry after that? I've heard it's ok to heat it in the oven. I don't want to do that (I'm not convinced that it won't alter the natural patina). Is it ok to rub the coin with a soft cloth to dry it? Is there any need to soak in water to re-balance the ph (especially after alcohol)?

4) What are the long term effects of an oil soak? It might darken the coin? Will it leave a residue?

5) Is there any advantage to leaving the coin untouched, with the crud and verdigris on the coin? I have tended to think that it's best to never screw with a coin. And now I have just put a beautiful 340 year old copper coin in olive oil. I don't like altering coins, but I would like to clean/conserve some of them.

6) I have a PVC problem with some coins, silver and copper. I am told that this should be removed ASAP, as it continues to damage the coin.


Thanks for the help!

windwhispersintrees

Electrolysis involves using a solution of baking soda & water, a stainless steel anode, and a power source. Try a Google search for electrolysis, coins, cleaning to get all the details of how to set it up. It's simple to do.
Here's what I've learned...coins that clean up best must have decent metal to start with...most dug up coins are pitted, and results can vary. Electrolysis is great however for solid coins with surface gunk, dirt & stains. Below are some photos of coins cleaned with electrolysis. The "after" photos were taken immediately after cleaning...I didn't try to photograph or create any subsequent re-toning to the coins.
Here's a before & after photo of a 1942d wheatie...not much green corrosion, but heavy dirt crust:

Here are the results on a silver half dollar...no green but heavy dirt. Electrolysis is great because it's non-abrasive. Rinse coin in clean water when done, and BLOT (no wipe, scouring etc.) dry with soft cloth.



Here's a test on a nasty 1952 jefferson. The coin has heavy pitting and green corrosion. Electrolysis softens and removes green stuff so you don't need abrasive cleaning. With electrolysis, you control how much patina is to be left on the coin.


Here's the cautionary conclusion. There are coins that ARE NOT candidates for electrolysis. Here is one. An 1819 Large Cent dug from a field. Note the overall green patina. More importantly, notice the pitted cratered areas. Both of these are clues that there's no surface metal left. This coin should be left as is. I know this because I tried electrolysis, but the coin was toast. The corrosion you see was the only detail left on the coin. It's now a dateless, ugly copper slug.
So, the moral of the story is: experiment with electrolysis and all cleaning methods. Use your junk coins. Learn what works & what doesn't. Good Luck.

MacCoin

the olive oil didn't do muct for me but windwhispersintrees that electrolysis is something I going to look into!

agentjim007

If no one said it yet try WD-40 works great on copper crust.

1jester

Thanks, windwhispers (and others). I will eventually try out that electolysis idea; it seems suited to many problems. Sorry about your dateless copper slug. I guess you learn from experience if the coin will be toast like that.

1jester

Olive oil soak update.

After about a week soaking, I took them out and lightly and slowly brushed some of them with a soft toothbrush (I didn't have a toothpick), one coin for about an hour. All the black crud between the devices came off, except on the 1/2 Anna, which I put back in for further soaking. I didn't notice any darkening of the coins. They cleaned up perfectly, without visible damage to the surface, or toning/patina. The coins look clean and still have their beautiful rich patina on them. With one exception: I wanted to dry off the olive oil, so I took the 1821 cent first and lightly cleaned it off with soap and water, and basta--it turned a light, steely gray. HORRIBLE!!! If I had known, I wouldn't have used soap and water. Later, I put oil back on it but the beautiful chocolate brown patina is gone forever.. I should be shot for damaging a rare Large Cent. Otherwise, it's ok, but it's damaged in my opinion. So with the others, I simply dabbed off the olive oil and have left them out to dry further (they look dry already).

Thought you'd like to know. Any comments?

Kejun99

1Jester!

That's terrible !! But i can't help think that you haven't damaged the coin unless there was lye in that soap that you useds... or something that reacted violently with the Olive Oil... ! What was the temperature of the water? Was it cold?.. it may have solidified some ingredients in the oil and/or soap... Did you try holding coin under just warm running water increasing the temperature gradually to possibly dissolve the oil/soap ingredient? The steel grey color of which you speak sounds like solidified grease !... which could have been in the soap !!! Don't give up... It needs a Doctor ! What about that Preservation company ? Could they run some tests without undue cost, time, And is the coin solid enough to withstand further testing? I feel sorry for you and the coin..
And at the same time thank you for sharing with us your experience...
Ken

Kejun99

JD,
Thankyou for this extremely informative and helpful Thread !
Ken

1jester

Thanks for the advice and sympathy, Kejun. I'm in Poland, so I don't know what the ingredients of the detergent are, but the company's Colgate-Palmolive "AJAX", antibacterial soap, but produced in Poland.

Here's another clue to the mystery. Prior to soaking, the coin looked like it had a slight film of something on it (on top of the beautiful dark patina), and I thought it may be PVC poison, hence the reason for soaking in the first place. After the soak, I couldn't tell if that film was there or not, but the patina was there, until I washed it off, using cool running water. I could feel the texture of the coin change as I applied and immediately rinsed off the soap; it became very grippy, not slick. And the color changed immediately. Presently, the coin looks solid and very nice, actually, but the color is off. I'm sure the metal is solid, and problem-free. And there's no trace of that film I alluded to. Perhaps the film was some kind of contamination, and soaking and/or the soap took off the film along with the patina?

Any guesses?

dakra

Since I have a baby, I decided to try some of the baby oil we never use. Three of the coins (Copper) I have in there now look much better than when I originally placed them in there... I wish I had before and after photo's. I am going to do another test but this time, I will scan them before I soak them. These are test coins as I'm not sure what's in baby oil. I generally wash the oil off with "Dawn".

How about storing coins? I'd like to store some Nickles, Dimes, Quarters and Pennies away for a few years. I want them to have the same color..etc..etc... What is the best way to do it? Mineral Oil? When do I have to change the oil?

Thanks....David

oreville

ttt

Bikingnut

Before the oilive oil:



After the olive oil:



The second picture is a little dark and doesn't show the attempted cleaning at some point in the coin's life. I was pleased with the results though, and it is now in my Dansco 7070. Here's the link to my original thread.

Link

Dennis