Cleaning Old Copper?

Buellride

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Hello, just wondering if a lemon juice soak is a good method for cleaning up old/older copper? I recently dug a 1854 Canadian Bank Token (see here : https://metaldetectingforum.com/showthread.php?p=3042982#post3042982) and I want to pull more details on the coin.

I typically soak my copper in hot hydrogen peroxide but recently saw someone I respect as a hunter, use lemon juice for a 24 hour soak.

Thoughts?
 
Hello, just wondering if a lemon juice soak is a good method for cleaning up old/older copper? I recently dug a 1854 Canadian Bank Token (see here : https://metaldetectingforum.com/showthread.php?p=3042982#post3042982) and I want to pull more details on the coin.

I typically soak my copper in hot hydrogen peroxide but recently saw someone I respect as a hunter, use lemon juice for a 24 hour soak.

Thoughts?

I actually try not to use anything if i can, and at most i use distilled water soaks between tooth picking.
 
Be real careful when using something with an acid back round to remove the crust from copper. It can, and will destroy the details it has. Part of that crust comes from the base metal, and after it is gone what you have is a pitted out piece of disappointment. I know, I have been there.
 
Be real careful when using something with an acid back round to remove the crust from copper. It can, and will destroy the details it has. Part of that crust comes from the base metal, and after it is gone what you have is a pitted out piece of disappointment. I know, I have been there.

hoser…..I believe you meant to type acid "back ground", but can you explain ? What's an "acid back ground" ? I'm not being critical....just trying to learn.

Thanks,
ToddB64
 
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First step after simple washing for most copper would be stopping further corrosion..mineral oil is fine..that's advice from my very reputable local coin shop..my best friends uncle was the original owner..they deal in some nice coins...take it or leave it..the idea is to lock out oxygen and water..then it's up to you..but in the end..if there was any corrosion..it must be sealed..or further corrosion will be certain...
 
First step after simple washing for most copper would be stopping further corrosion..mineral oil is fine..that's advice from my very reputable local coin shop..my best friends uncle was the original owner..they deal in some nice coins...take it or leave it..the idea is to lock out oxygen and water..then it's up to you..but in the end..if there was any corrosion..it must be sealed..or further corrosion will be certain...

That is partly true.
Before sealing you must ensure all water is removed. Alcohol works to de-hydrate the coin.

Then there is 'Bronze disease' that continues even if sealed from additional water and air. This is a cycle of CuCl <-> HCl.

See the tech paper in this thread for details:
https://metaldetectingforum.com/showthread.php?t=263378
 
That is partly true.
Before sealing you must ensure all water is removed. Alcohol works to de-hydrate the coin.

Then there is 'Bronze disease' that continues even if sealed from additional water and air. This is a cycle of CuCl <-> HCl.

See the tech paper in this thread for details:
https://metaldetectingforum.com/showthread.php?t=263378

Yes.. important step.. I failed to mention it.. I like grain alcohol... general consensus is that there is no perfect restoration for corroded copper...under magnification they are ugly... but you can make them pleasing to look at...
 
Yes.. important step.. I failed to mention it.. I like grain alcohol... general consensus is that there is no perfect restoration for corroded copper...under magnification they are ugly... but you can make them pleasing to look at...

I use Denatured alcohol (methylated spirits) to dehydrate.

Since most of the ones we dig have 'environmental damage' they are only worth a dollar or so.
Pleasing to look at is a good goal.
 
I use Denatured alcohol (methylated spirits) to dehydrate.

Since most of the ones we dig have 'environmental damage' they are only worth a dollar or so.
Pleasing to look at is a good goal.

Yeah..good advice...That's probably better than grain alcohol if you get the stuff that's over 95%...the less water in it then the better it is.. I just happen to have a gallon or two of grain alcohol that's been sitting here for years..so I use it..

Depending on the coin.. I might only rub it clean with sodium bicarbonate .. or experiment a bit with different chemicals.. I've had some nice results actually.. however..it is a deceptive practice..or can be... like most folks I prefer an uncleaned coin.. certainly..but for environmentally damaged coins.. I see it as restoration..simply to preserve.. in the name of eye appeal or to reveal identity...
 
hoser…..I believe you meant to type acid "back ground", but can you explain ? What's an "acid back ground" ? I'm not being critical....just trying to learn.

Thanks,
ToddB64

Hi Todd, you are right I misspoke myself. But yes anything that is an acid can take more of the "crud" off than you want. The worst one being something like CLR lime and rust remover. I destroyed a nice old Indian head trying this. Vinegar and salt is less harsh but it too can leave your coin looking bad. Now the only thing I use is hot hydrogen peroxide to soak an old coin in. Or an olive oil long soak. Also if it's an old IH that has that beautiful bright green patina on it, all I do is wash it with soap and water and leave it alone.;):yes:
 
Hi Todd, you are right I misspoke myself. But yes anything that is an acid can take more of the "crud" off than you want. The worst one being something like CLR lime and rust remover. I destroyed a nice old Indian head trying this. Vinegar and salt is less harsh but it too can leave your coin looking bad. Now the only thing I use is hot hydrogen peroxide to soak an old coin in. Or an olive oil long soak. Also if it's an old IH that has that beautiful bright green patina on it, all I do is wash it with soap and water and leave it alone.;):yes:

Thanks a bunch hoser !

Great information for those "That looks like a valuable copper coin!" coins.

(Hard copied for my "Coin Cleaning" folder for future reference.)

ToddB64
 
I never do more than rub and toothpick. I've killed several coppers using all kinds of full proof methods.

Same here.
Here is today's find with only careful tooth pick rubbing and a little nose oil.
Any more and what little readable detail is there would be lost.
It is a Bank of Canada half penny Token 1850.
 

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