How to get crud off of early copper?

FrattLaw

Got a 1846 tall date large cent for $20. It's in real nice XF-AU condition, but its got some crud on the obverse and reverse. Is there anyway to soak this off. I thought I remember seeing someone post something about olive oil.

Thanks
Michael

lordmarcovan

Depends on what kind of crud you're talkin' about. Olive oil is the time-honored method of those who collect ancient coins. Slow but safe.

I often use Vaseline to remove loose dirt and grime without affecting the coin's color, and a wooden toothpick to get gunk out of crevices and lettering on the coin. (Very carefully, of course).

Note about color: if you remove a hardened gunky spot like tar or paint or whatever (usually with acetone), this CAN cause a change in the coin's color, because the area beneath the crud will not have toned with the rest of the coin.

melikecoins

I have been soaking some pennies in olive oil for about a month now.
What is the next step?
Glen

lordmarcovan

Wow, a month.

I've never been patient enough for that.

Try scrubbing lightly with a toothbrush after your olive oil soak.

jonesy

You guys are real. Stay cool!!
Glenn

BigD5

I use Blue Ribbon Coin Conditioner. Works great on copper without messing with the color. A moistened toothpick end usually does the trick also.

FrattLaw

Its just lite surface crud. Some of it has gotten into the crevices and around the stars.

Should I try the olive oil and see what happens? Olive oil shouldn't harm the coin, should it?

Interestingly enough this coin as has a die break/cud on Liberty's forhead. I wonder if this is a variety.

Michael

lordmarcovan

Yeah, olive oil is one of the safest methods, but it's soooo sllooooooooow.

The Blue Ribbon BigD5 mentioned is a good product, too.

FrattLaw

I forgot to ask, how do I get the olive oil off the coin after it has soaked?

Thanks
Michael

crito

Now he can sue you when Blue Ribbon turns his red copper brown

Coppernicus

Coppernicus

OOPs!!

Olive oil works but takes a long time and it will turn rancid over time. I use mineral oil (won't turn rancid), doesn't harm the coin, but also takes a long time. I have about 50 Lincolns that have been soaking for almost a year now and I'm nearly ready to take them out, rinse, and submit! Color has stayed steady at least, and improved slightly on some. No deterioration in any of them. BTW, very very very minor surface carbon spots (did I emphasize tiny tiny tiny and thin thin thin?) have weakened and do not any longer detract from the eye appeal (at least without magnification.) Larger spots are still there and UGLY!! No cure for those puppies.....

lordmarcovan

<< <i>I forgot to ask, how do I get the olive oil off the coin after it has soaked? >>



I just gently rub my coins with a clean, soft cloth. I find an old T-shirt works well.

BigE

I have had a 1867 IHC soaking for 2 years in olive oil now. It was totally black at one time but had nice smooth surfaces. It is now nice and brown. One thing you have to watch out for Fratt is not to take the coin out every month or so and wipe it, the Indians ribbon now has a slight bright copper area worn into it---------BigE

agentjim007

WD40..this is not a joke

Libertad

I have used the aluminum foil and hot water with a tablespoon or so of Arm & Hammer washing soda (not baking soda) with fairly good results on corroded nickels (buffalo). It definitely improves the brown ones but doesn't seem to affect the black ones.

Put a square of aluminum foil in the bottom of a pyrex or cyramic cup, the washing soda on top of the coin, and pour in a bit of really hot water. The whole thing fizzes like crazy for about 6 or 7 minutes, then stops, with the aluminum foil becoming a bit ragged and dark, and the water turning dark as well. Smells pretty ugly.

I've repeated a couple of times with slight improvement each time on the brown corrosion. I haven't tried with copper coins, but the nickels are 75% copper/25% nickel. It doesn't help verdigris much either, but the metal is not affected with the reduction reaction, just the oxidation. Whatever is underneath is revealed to some slight degree, whether damage or smooth surface.

Good luck !

oreville

I concur with coppernicus. Mineral oil works best and does not turn rancid like olive oil.

You do NOT rub the coin in a soft cloth to remove the oil when done. Instead, place the the coin inside soft tissue paper and squeeze together. Repeat. Then gently move the coin to a drier area of the tissue paper. Then aqueeze again. keep repeating this process until the coin is dry. But doing it this way, you are not causing any damage to the coin.

1jester

I agree with Oreville's method of removing the olive (or mineral) oil. Rubbing should be avoided, especially under pressure. I use new soft paper towels; they're cheaper than a scratched coin. If you prefer, you can then put the coin in the sun (on a window sill) for a few weeks, turning it over every week or so. This method hasn't toned any of my coins thus treated, only made them dry to the touch afterwards. I think it's a good method.

By the way, for those using the extra-virgin olive oil soak, it's necessary to change the oil for fresh oil every month or so, because the oil takes on the dirt and grime of the coin, and even smells metallic. Change it regularly, and you can also lightly brush the coins (with a super-soft toothbrush, with the oil still lubricating the coin--still, be very careful) if there's a lot of verdigris or other crud, then put them back in the soak.

And as far as toothpicks are concerned, I think they are EXTREMELY risky to use, even if pre-soaked in oil. They are simply very abrasive, and will scratch your coins, sometimes terribly, especially if you slip. I'm not saying I never use a toothpick, but it's a calculated gamble, and I try my best to avoid them altogether. Really, if you're insistent on trying a toothpick, use it sparingly and try about 100 test (junk) coins first.

Good luck.

Steve27

I would avoid any/all mechanical methods (i.e. no brushes or toothpicks). These methods are for coins found in the dirt with metal detectors.

To remove olive/mineral oil use soapy water (soap molecules are oil soluble at one end and water soluble at the other). Then rinse with pure water.

1jester

Steve, I've had some terrible trouble with using soap (ordinary dish soap)---my copper coins turned a light steely-gray color. Fortunately, putting oil back on them got them back to nearly the original color. I don't know what else to say, but that was my experience. Now I'll never use soap again.

Steve27

Interesting jester, I'll have to try some experiments.

dorkkarl

next time your at a major show, ask tom-reynolds. he's a world-class expert

K S

maddogale

Michael, to remove the olive oil or WD-40 or mineral oil safely, use rubbing alcohol, as these are both organics and the oil will be dissolved safely by rinsing without any wiping needed. You may have to rinse with a good bit, but rubbing alcohol is cheap......just don't smoke while you are doing it!!

VonZipper

Try a good quality soft sponge, wet and lather it up and put the coin in the middle and fold sponge over it. Do a light circular motion to get soap all over coin then rinse off, pat dry and dip in acetone and let dry.

oreville

I have used pat drying, air drying, acetone, alcohol and soap and water to fast dry the coins.

Quite frankly the fastest method that is safe is pat drying then using a hair dryer. Rinsing the coins does increase the danger of residue spotting.

I do like acetone then a distilled water rinse the best for silver coins but NOT for copper. I just don't like the look of it as much. Yes soap and water does not seem to work well...also increasing the chances of residue spotting.

NEVER try the hair dryer/blower after using acetone! You won't need to! You won't be there afterwards either!

Last but not least....olive oil does tend to make copper coins darker in appearance whereas mineral oil is a bit more stable color wise for the copper coin but also slightly darkens such circulated red brown and brown copper.

1jester

Steve, yes it couldn't hurt to experiment a bit. No doubt there are soaps with different ingredients.

Acetone does indeed work well to extract all oils from the coin. I sometimes place them in an acetone soak for a few hours, then take them out and immediately transfer them to another jar of clean acetone, then another. This is to remove all traces of the dirt that the first acetone bath contains (especially important if the coin is a proof).

NEXT QUESTION: is it better to remove all traces of the oil off the coin, or is it better to have minute layer of oil on the coin, in order to better preserve it? I've heard that when originally minted, the dies are lubricated, which transfers a microscopic layer of oil to the newly minted coin. I don't know if this is true or not, but if so, wouldn't it make sense to say that coins are "born" in oil, and therefore it isn't too radical an idea to leave a tiny bit of oil on the coin? In my personal opinion, I feel that a bit of oil doesn't hurt, especially if the coin has old toning (especially on copper). What are your ideas?

1jester

I just read Oreville's last post. He pointed out something I've come to agree with. I don't really like the look of toned copper coins after acetone. They seem too "dry" looking. On the other hand, after oil, they tend to gleam more, and this seems more natural. For red cents, I think acetone doesn't leave any bad appearances. But for older copper, I don't like to use acetone to dry them. In fact, I might use acetone first to remove some PVC, then soak them in olive oil and pat, then air, dry them in the sun.

MacCoin

I have used acetone to get the green crud off silver but after its gone the is usually pits under it so now I very careful not to buy coins with curd on them.

1jester

Mac, if you're talking about PVC disease, I know exactly what you're talking about. It ruins coins, plain and simple. Unless you can catch it fast enough, before it starts corroding the coin. That's what I'm talking about, using acetone to remove the PVC film/residue. Sometimes I'm too late, and the film has etched a microscopic layer into the coin. Other times I've seen huge pits in the coin. It's devastatingly sad. Why is PVC even for sale? I can't believe it.

oreville

A number of EAC members have often preferred that oily satiny look of early copper. It helps to highlight what luster remains on the coin as well as hedlp the light reflect better off the coin.This is one of the reasons I prefer to allow a very small amount of oil left on the coin. Yes indeed, coins were born with some machine oils which is why I actually love the use of mineral oil in flaming red BU copper!

I happen to feel that if mineral oil cannot get into PVC film/residue and dissolve it then more intensive methods will further damage the coin.

abuell

To soften up the crud use xylene, a medical solvent available at most drug stores. To dig crud out of recesses on the coin use rose thorns - they will not scratch the copper.

1jester

Abuell, thanks for the tip about rose thorns. I'd never heard of that, and will try it out.

oreville

Abuell: Likewise, rose thorns?

You leave one or more on the stem and trim for proper handling and location?

It does make some sense, a slightly softer version of wood. I assume freshly picked thorns?

I had used xylene but I found that if you accidentally put it on the undamaged surface areas it id not agree with such surface too well as it was pretty strong stuff. I wonder if I had a film of mineral oil only on the better areas of the coins if that would protect such areas from the xylene? Worth a try as I never thought of that before.


Thanks for the suggestions.