MILK SPOTS

General discussion board about VAMs, but no buy/sell offers
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Longstrider
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Joined: Tue Jul 03, 2018 9:12 pm
Location: Mojave High Desert

MILK SPOTS

Post by Longstrider » Thu Feb 06, 2020 10:32 pm

I was wondering what causes milk spots on our silver coins? I appreciate any ideas. Thanks..

colwillys
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Re: MILK SPOTS

Post by colwillys » Thu Feb 06, 2020 10:40 pm

Mint did not wash all the cleaning solution off the planchets .

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Longstrider
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Location: Mojave High Desert

Re: MILK SPOTS

Post by Longstrider » Thu Feb 06, 2020 10:47 pm

@colwillys Thanks Col. I have heard that is the most likely reason. Is there any other likely causes. I know that Canada had the same problem with their Maple Leaves silver coins. They seem to have corrected it. I'm trying to do a small study so am looking for as many possible reasons as I can get. Thanks again.🐍

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UncleGildy
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Re: MILK SPOTS

Post by UncleGildy » Fri Feb 07, 2020 1:00 am

That's what I've heard too. Then recently, I stumbled across this youtube which was quite interesting.
https://www.youtube.com/watch?v=7sJSwKe5Ev8

I'm not endorsing anything here, but I found it interesting that he mentioned cloudy ammonia, after just recently reading about sudsy ammonia here. I have a bottle of sudsy ammonia I picked up at the local hardware store, but have not yet mustered the courage to try it out. Interesting that it may also be effective against milk spots.

On a related note - I have a coin that was "improperly cleaned" with some agent, and I swear there's a residue on it that just ruins areas of the coin :(. I wouldn't mind a little loss of luster or evidence of polishing, as much as this off-white milky fog that looks like a coating or contaminant. It looks especially bad under the scope with LED lighting and polarizing filter set to even the most optimal setting (or maybe the polarizing filter of the Dino Lite I'm borrowing makes it look worse).

Anyway - perhaps the cause is a borax-like residue on the mint equipment, and perhaps sudsy ammonia would resolve it - I don't know. Just too chicken to try.

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