olive oil.....does it really work?

[hollowpointred]

everyone always says to soak copper coins in olive oil. i understand that this process is supposed to take months if not years to work? my question is, has anyone actually soaked a coin that long and if so did it work? if anyone has any before and after pics i would love to see them. in my limited expieriance, i havent noticed any differance by doing this,other than making the coin oily.

 

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[Michigan Badger]

Olive oil can work to remove some surface hardened dirt but it won't do much for heavy corrosion. The guys on the ancient coin forum preach olive oil 24/7 but every time I've tried it on ancient encrusted coins I ended up having to do distilled water soaks, lye, or electrolysis.

I know someone who has coins soaking in olive oil now for nearly 5 years and they're still not ready.

Lye is awesome for cleaning SOME corroded coins (mainly ancient coins) and even some silvers but it's nasty stuff. I've got a scar on my hand from lye. Get it into your eyes and it's bye-bye sight.

If water soaks don't work one could try the aluminum foil and salt water (or baking soda water) trick described by everybody and his brother on here. I cleaned a bronze spoon with this method.

I could write a book on coin cleaning but I won't do it here.

Best of luck.

 

[hollowpointred]

does the foil and soda thing work on copper? it sure does work on silver.

 

[Michigan Badger]

I haven't tried it on copper coins but it worked on a copper base spoon.

I'd try it out on some junk item first before using it on anything you'd like to keep.

 

[Monty]

I had a few cookie coins soaking in olive oil for nearlly a year. Finally it went rancid and I tossed the whole mess! Not my cup of tea.....or oil. Monty

 

[Detecting Fool]

Ive only tried olive oil on my common date coppers. Yes its worked. Yes its cleaned them up nice. As a coin collector, I would not recommend cleaning anything, especially if you looking to sell, or if it was a rarity. A cleaned coin is worth much less, maybe even nothing, then a coin in its natural state.

Anthony

 

[Jason in TN]

Olive oil does work. Have used it to clean may old wheat Penny's. If you want to rush it along hit them with a soft bristle brush now and then. I do not buy the don not clean your coins thing. If done right they look better and will sell for more money instead of less. You can damage a coin by cleaning it but if you clean it with out damaging it it will sell for more money than a coin covered in crud. If you want to sell your coins forget about coin dealers Ebay will bring you much better returns.

 

[bk]

I have soaked some of my nicest copper coins in olive oil for well over a year. What I have noticed is that, if you have a nice shinny green patina on the coin, the olive oil will keep the coin shinny, but will tone it more of a dark copper color. It also seems to soften the green "crust" on really corroded coins.
I have not seen any sign of pitting either. It must be doing something because the olive oil has turned greener than its normal green color.

 

[JakePhelps]

If done right they look better and will sell for more money instead of less.

But if you try and get it graded they will send it back as Cleaned and grade it alot less, they can tell. Maybe an unsuspecting ebayer would buy it though.

 

[Jeffro]

Well, my two cents. Olive oil isn't really a "cleaner" per se, it just helps loosen the crud while maintaining the coins natural patina. I use olive oil, and after a few days, gently remove the crud with a toothpick. If you need to, do it again and again until you get down to the coins suface. Don't be in a hurry, and don't try and pry off any really big chunks. If you really want to, you can boil or steam the coin to remove any remaining olive oil, I guess. But the olive oil won't damage a coins surface like cleaners will.

 

[suffolkboy]

There is an easier way to give your copper coins/bronze artefacts a lovely deep patina and hue.It doesn't take years either! First wash the 'bits' in boiling water to wipe out the 'ground salts',then,if the piece is not flecked with verdigris dunk it in a jar of petroleum jelly for a fortnight.
Take it out,wipe all excess off with a cloth and notice the difference.
If you need to take the 'coat' off,just rinse it under the hot tap and the item will go back to its 'lighter guise'.

 

[Angela (Australia)]

Electrolosis and oil

Hi all,
I occasionally use electrolosis to clean up heavily dirtied or gunged up relics, but only soak for a few secounds, and keep a eye on the process, or you can corrode the relic. Also I do use a bit of vegie oil and a toothbrush to scour the dirt off coins. It takes a bit of brushing, but doesn't damage the coins. And once done, just wipe off the excess oil, it really brings up the designs on my coins.
Cheers Angela

 

[Michigan Badger]

I've gone a little back and forth on the oil soak issue.

The results one gets depends upon the objects to be cleaned.

Some artifacts are merely dirt impacted and others are deeply corroded. The dirt impacted items will clean with oil soak. However, the very deeply corroded usually require much more severe treatment.

I've learned that usually the cleaning process involves a mix of methods. I might start with an oil soak--then try lye--then a short electrolysis treatment--then maybe a little copper brush work, etc.

Every cleaning project is different.

 

[Angela (Australia)]

And I agree with you Badger, different methods of cleaning are sometimes required as to the type of object and it's condition.

 

[Monty]

I was using virgin olive oil. Maybe I should try the Hoochie Mama kind? Monty

 

[MUD(S.W.A.T)]

NO!

 

[Southcacalaky]

I'm Half Italian, I only use it in my food, HH Art...

 

[Rusted_Iron]

As far as I know, the primary mechanism of olive oil soaking is this:

Corrosion particles have an affinity for the coin and for each other. Over time (a lot of time!) the oil "creeps" in between the particles and the coin's surface, reducing the strength of their interactions toward each other and the coin's surface. This allows them to float away. I'm oversimplifying things here- the surface chemistry can get rather complex, but I do not believe it actually removes from the metal surface of the coin. It doesn't add, either, with the possible exception of the darkening that some people report. Darkening of the copper is most likely from trace sulfur compounds in the oil, but I'm also thinking it could be from oxidized (rancid) molecules in the olive oil that produce copper oxides over a great deal of time. Olive oil is a plant product, and plants contain sulfur (just like animals do).

I have not researched yet whether the cleaning mechanism of olive oil is also due to traces of free fatty acids in the oil. This may in fact be true. However, mineral oil will also work (not sure if it works as well, need to do experiments), and this does not contain fatty acids-- just straight-chain hydrocarbons.

I don't know about those grading outfits, but I personally have no qualms about buying a coin that was olive oil soaked, if that's all that was done to it. If a coin is nothing more than a corroded copper slug with no detail, you have nowhere to go but up. I've heard conservators say they like electrolysis, but I have some big reservations about it. On copper coins it can quite easily give the surface an overcleaned appearance. It also runs the risk of chemically reducing some of the corrosion back into a metal coating that doesn't want to come off the surface... this would essentially be "re-plating" the coin with its own former metal content. Typically, though, most of the corrosion that's reduced to metal will actually flake off the coin and into the electrolyte.

 

[BuckleBoy]

I have not personally tried olive oil, but as a numismatist, I would urge against ever cleaning or buffing silver coins! That said, all I can do here is outline the procedures I use:

for copper coins: just running water and a toothbrush.

for silver coins: hard running water (to carry away the dirt that is loosened rather than let it rub against the coin surface again) and a camel's hair make-up brush. On silver coins, I resist the strong urge to spot clean or field clean them agains my jeans to see the dates. Hence I carry a camel's hair brush (inexpensive) with me on my trips.

Unless you "sucker" someone on e-bay (which I would hope none of us would ever aspire to!), a coin collector will always know which coins have been cleaned. I like to err on the side of minimal cleaning. If the collector buys a valuable coin from you, any resoration work is then their responsibility and not yours. Let them do it. Don't be responsible for destroying or lessening a coin's value. (whew!) It is pretty certain that they won't be using wire brushes or electrolysis!