Author Topic: Open Resource Collaborative Silver Coin White Spot Amelioration/Removal Project  (Read 1653 times)

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Offline KeepOnTrying!

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Open Resource Collaborative Silver Coin White Spot Amelioration/Removal Project

White spots are unsightly on silver coins and reduce their grading quality and numismatic potential. Despite widespread knowledge of this problem coins that subsequently develop white spots are still being minted indicating that even the mints either don’t have a foolproof preventive measure or don’t apply it consistently to eliminate this problem completely.

As I continue my start and go process of rehousing my OMP and slabbed coins in archival bags I occasionally come across silver coins with white spots. I am sure those spots were not there when I purchased the items (except the 2013 1st Expo Panda medals). The question is what to do with those coins.

Whilst the regular conservation techniques usually eliminate copper spots on gold coins they have not been shown to be consistently effective for removing white spots on silver coins. Furthermore electron microscopy suggests that white spots are not just a coin surface discoloration phenomenon but involve structural disruption of the coin surface. So just washing the coin with a detergent-type solution is not likely to remove the problem (I think).

So what is the solution? Who has practicable suggestions for removing these white spots? This cannot be rocket science. There has to be a solution somewhere!

I’ll post in segments to avoid information overload.
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Offline KeepOnTrying!

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Objectives of White Spot Removal.

Since there is a disruption of the coin surface it is not realistic to expect that any white spot removal process will restore the integrity of that area of the coin. Therefore less ambitious objectives should be acceptable.

I feel that following the removal process naked eye non-visualization of the white spots can be an acceptable compromise; the coin looks good and that is better than the prior unsightly white blotches.

The resulting coins should be acceptable for grading by the reputable companies such as NGC and PCGS.

The coin grade following white spot removal may not necessarily be similar to the pre-white spotting grade; it may be less. The question is how low to set the bar; ???MS/PF 65-66??? I will be happy to hang on to my coins if the white spots can be eliminated even if that drops the grade by a few points.

What other objectives can we stipulate upfront before considering possible removal methods? What else am I missing?
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Offline KeepOnTrying!

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Possible White Spot Removal Methods

1: Polishing out the white spots with micro-abrasive methods. Probably a non-starter. Should fall under the coin-doctoring methods that TPGs do not accept.

2: Spot treatment with a “removal” solution, using cotton tipped swabs for example, followed by a general coin rinse and additional bathing in required solutions.

3: A global coin treatment with the appropriate solutions followed by rinsing and additional bathing in other solutions or liquids.

4: What are your suggestions? If I knew the correct procedure I would already have carried it out and presented the results here! We have a lot of people here with varied talents and professional backgrounds.

http://china-mint.info/forum/index.php?topic=3645.0
http://china-mint.info/forum/index.php?topic=6767.0
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Offline KeepOnTrying!

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The Guinea-Pigs!!

I have two 2010 1oz silver Panda coins for this experiment (PCGS MS70). See attached photos. In their current state they are not worth more than their bullion content. I don’t care if they get damaged during this process. I am sure everyone here has white spotted coins they can also experiment with. I’ll wait for a week or two to see if there are any workable solutions offered here in this forum before cracking them out.

PS:  Please regard this as a serious exercise but not that serious as to generate strong feelings. Let’s relax and enjoy this. We may never find a solution. But that is what they thought before we landed a man on the moon!

Okay, down to the lab. Like I said, I am ready to flush these coins down the drain!

Your suggestions will be appreciated.
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Offline 1668Chris

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Not aware of any process or method to remove white spots.  Much has been written on this topic.   You might want to call NCS to see if they have any suggestions.

Offline KeepOnTrying!

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Poconopenn posted a reference on white spots on another thread tonight: http://china-mint.info/forum/index.php?topic=3645.msg72160#msg72160

Acetone was mentioned as a possible white spot remover.

Does anyone have experience with using acetone for coin cleaning? Do you dip the whole coin in the solution or do you apply it with a q-tip swab on the spots? Do you let it dry or do you wash it off immediately? Do you rinse off with triple distilled water and/or soak in something else?

Lots of questions but thanks for suggestions!
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