Author Topic: Cleaning Coins in Lot  (Read 2662 times)

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Offline mlvs

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Cleaning Coins in Lot
« on: January 28, 2013, 01:48:38 PM »
Hello

I have around 500 well circulated coins in a bag.
Since its of more in number I dont prefer to clean it individually.
These are 1Re India Cu Ni coins (1980-1990).
Most coins have dirt, developed some green fungus sort of in it.

Will placing these coins in soap water/ diluted citric acid will help?

Even though the coins are of low value I am not interested to lose it due to corrosion or throw away.

Any other idea to clean such large amount of coins in single shot ?

Thanks
Madhan

Offline Figleaf

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Re: Cleaning Coins in Lot
« Reply #1 on: January 29, 2013, 12:38:47 AM »
It all depends on what the "green fungus" is. Some possibilities:

  • The coins were kept in a packaging of biological material in a moist environment. The green is mould. Buy a mild (something that requires a Mars suit and a mask is too strong) chemical mould killer and bath the coins. Follow the instruction for use of the mould killer religiously.
  • The coins were kept in inferior plastic. Remove them from the plastic and bathe them in acetone.
  • The coins have oxidized. I would have expected the oxide to be black, but you never know. You can't batch-clean them. Cleaning will be painstaking and individual.

Peter
An unidentified coin is a piece of metal. An identified coin is a piece of history.

Offline mlvs

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Re: Cleaning Coins in Lot
« Reply #2 on: January 30, 2013, 10:46:06 AM »
Thanks Peter.

I tried with soaking a single Cu Ni coin ( It was filled with black dirt) in coconut oil for a day and washed it with vessels cleaning liquid with help of soft toothbrush.
Left with so many scratches on the coin :(

Offline Figleaf

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Re: Cleaning Coins in Lot
« Reply #3 on: January 30, 2013, 11:06:07 PM »
Coconut oil does not make scratches. Neither does liquid soap. Either the toothbrush wasn't soft enough or the coin was already scratched. If it's the toothbrush, use a toothpick instead. Wood is softer than metal, so it won't make scratches.

In general, oil is good for copper, but doesn't do much to Cu-Ni. If you want to remove dirt, soapy water will do it (soap solves fat, which is what makes dirt hard.) If the dirt is caked and stubborn, heat the coin, cool it off rapidly (or vice versa) and attack dirt with toothpick. This method is a labour of patience and an individual treatment, unsuitable for batch treatment.

Your first worry should be to remove the green (see my previous post.) The black can come later.

Peter
An unidentified coin is a piece of metal. An identified coin is a piece of history.

Offline mlvs

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Re: Cleaning Coins in Lot
« Reply #4 on: January 31, 2013, 05:51:46 AM »
Will follow that Peter. Thanks

Offline bruce61813

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Re: Cleaning Coins in Lot
« Reply #5 on: March 29, 2013, 10:13:40 PM »
I am wonder about the "green fungus". If the coin is a copper based alloy, your fungus may be Bronze Disease". Take a look at the article at the top of this topic, it may be of help.


Bruce

Offline Alan Glasser

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Re: Cleaning Coins in Lot
« Reply #6 on: March 30, 2013, 10:00:03 PM »
Does anyone use Olive Oil anymore as a "caked on crud" remover? I have had some success with it but it takes time...days and weeks sometimes to see the stuff start to come off.

Alan

Offline bruce61813

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Re: Cleaning Coins in Lot
« Reply #7 on: March 30, 2013, 10:25:28 PM »
Olive oil is not much used anymore. One thing ,it is acidic, but only slightly, and is really slow. Not hours or day, more like moths or years.  I prefer a very high pH soap product that breaks down the organic matter the holds the clay particles together. Faster and far lass messy. Neutral to copper based, or silver coins.

Bruce

Offline Alan Glasser

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Re: Cleaning Coins in Lot
« Reply #8 on: March 30, 2013, 10:29:14 PM »
Thanks, Bruce.

I remember using Olive Oil many MANY years ago...it worked...but if I recall...it took a bit of my lifetime to work...now that you mention it. What soap would you use?

Many thanks.  Alan

Offline bruce61813

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Re: Cleaning Coins in Lot
« Reply #9 on: March 30, 2013, 10:46:23 PM »
 ;D one i designed myself. I has various water softeners type chemical and a good soap. There are 3 types and are sold under the Gringgotts name.  They are mentioned in other threads. Keven Sandes , Noble Roman Coins, is the retailer.
  I designed them for my own use, for ancient roman and greek coins. Kevin asked if he could sell them, and that was about 10 years ago.

Bruce

Offline Alan Glasser

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Re: Cleaning Coins in Lot
« Reply #10 on: March 30, 2013, 11:27:14 PM »
Hi, Bruce.

Ah ha! a clever collector you. Gringgotts??? May I assume you are not on my side of the Pond?

Alan

Offline bruce61813

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Re: Cleaning Coins in Lot
« Reply #11 on: March 31, 2013, 05:29:20 AM »
I am hiding in the middle of Illinois , in a very small village......

Bruce