Exclusive to silverstackers electron microscope images of white spot

Discussion in 'Silver Coins' started by bron suchecki, Jan 7, 2015.

  1. Golden ChipMunk

    Golden ChipMunk Active Member

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    The new Matt finishes

    Look like a spray on job to cover up the milk spot from occurring ; but hasn't spot them though
     
  2. Petridished

    Petridished New Member

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    Plastic is not air tight. Any plastic which will stain, ex. tomato juice, is a semi-permeable membrane.
    ex. 2 walk aisle of laundry detergent, or garden sprays, or any other concentrate "contained" by plastic.
    You will smell the contents of the HDPE plastic containers.
    Leave a sealed plastic jug of paint thinner on shelf for 2 yrs.
    Less will be there.
    Not like the old metal can in Grandpas garage still full.

    Plastic bags definitely reduce exposure, with limited life span.
    A food vacuum bagger with triple layer plastic/aluminum/plastic bags and an oxygen absorber is NASA space crazy for coins, great for food.
    I tried such on OG walnuts.
    Supposed 18 month shelf life in a jar.
    7 years later from above triple layer bag, they taste like this years harvest.
    I had misplaced that bag and I am surprised and continue to eat the $15 USD/lb ancient walnuts.
    Not dead yet.

    I should seal some 2015 Kangaroos I purchased and test against air-tite.
    One does have RCM imitation like milk spot, and online dealer had warning of posted.
     
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  3. Vezpit

    Vezpit Member

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    Any new information regarding the milk spots? Last post was some time-ago.
     
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  4. Vezpit

    Vezpit Member

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    Have noted that several coins (Phills) where heavy milk spots occur, are the first areas to on the coins to become tarnished. Is there a chemical relationship? Ag2S, silver sulfide & AgCl. Did find the following from Collectors.com: A few years back when the $50K reward [which I don't believe was ever claimed] for a means of removal was being offered by PCGS, I had an acquaintance analyze one badly spotted ASE removed from a NGC holder. We used a technique called ESCA [electron spectroscopy chemical analysis] or XPS x-ray photoelectron spectroscopy which is useful for the analysis of small amounts of materials on surfaces. The only element we found [other than silver] was chlorine/chloride. https://forums.collectors.com/discussion/876446/what-causes-milk-spots-on-silver-proofs This seems to confirm the reaction of chlorine as noted previous in this forum. The blog also suggest that HCL (hydrochloric acid) is used to wash the coin/sheet of silver & may be responsible. If this is the case, neutralizing with an alkaline solution should prevent milk spots. Would think that the Mints would have already tried this. Any current info?
     
  5. Noxx

    Noxx Member

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    I think it's an etching chemical that is causing the milk spotting. That's probably how they get the different sheens on the coins. And I've noticed it seems to be more and more popular these days to have 2 or 3 different sheens on one coin. Different parts of the coins having different sheens to give it a neat and unique look. But they aren't washing it off well enough.

    I got a really bad batch of milk spotting on some privateers. I mean REALLY bad! It's obvious a chemical like a strong etching chemical did this. And it was only on the reeded edges. So the face didn't have any at all. Probably washed it off the face well enough and it dripped down the edges. I scrubbed it off with a rough pad and some baking soda. Looks much much better. But still some visible. I'm going to go buy some brasso now and a polishing wheel to finish it off. I know what you are thinking. DON'T ever use brasso on silver!! But that's the exact reason why you should with milk spotting. Because it should take a very fine micron layer off. It should remove the extreme top layer where the milk spots are and look brand new. On the reeded edge it should look totally fine. On a coin face it will change the sheen of course. But to me I wouldn't care. I'd rather look at a super shinny coin face than a horribly spotted one. I'd imagine most people would too and you'll at least keep some of the value better than leaving it with ugly milk spots on.

    I also have some Maple leafs that have milk spotting all over. I'll test one of those too but on the face and share the results.
     
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  6. Noxx

    Noxx Member

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    Ok so right after that post I ran down to Home depot to get the Brasso and polishing wheel. And started on my 2 oz Privateers. They are thick and when I used to stack them the milk spots were so bad it looked like zebra stripes down the stack. Really really bad. They did a number on them somehow. I wish I had started with the Brasso first and took a picture before the other day I did that original removal with the Baking soda. The baking soda had greatly improved it but it still was noticeable when you looked at them.

    I applied some Brasso paste to the entire edge of the Privateers. Then used the buffing wheel attached to my drill. It's a very small wheel. I buffed it for only a short time all the way around. The paste started turning black. So it was definitely removing some minute amount of silver. I then cleaned it all off with soap and water and a tooth brush. It looked perfect! I could not have sold them the way they were before. Now they look totally fine! I did all 10 of those privateers. It saved those rounds for sure. I would have no problem selling them for the going rate as any others.

    Now about the maples. The brasso took the milk spots right off. But the mirror finish on the queens face now had micro scratches. And some overall slightly duller look to the overall coin. Just barely though. What I'd need to do now is get a very fine polishing wheel and buff it to a fine finish again (and maybe some real silver polish?). I've never done that, so I don't know how well that works. Supposedly you can get a mirror finish though if you know what you're doing. Realistically I'm not going to get around to that though. I'm not worried about it right now and will probably experiment more when I'm done remodeling my house at the end of the year. For now I'd say don't do it on the face of any coins unless you want to experiment further and also know how to polish back to mirror finish. But it definitely takes the milk spots off. You'll just have to bring back the perfect mirror finish after.
     
  7. pastey

    pastey Member

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    @Noxx you wont get the same finish achieved from highly polished die pressed under enormous pressure onto blanks. The perth mint has a unique and sought after minting process that even their blanks are stamped out at a proof like level of polish. It's all in the die, the effort on what goes into polishing these dies is on another level...Mints around their world buy their blanks. The minting process creates a polish you will never get from buffering the metal.
    Unfortunately the Perth Mint produced a series of low quality BU coins. Guess the year...even once arrived in an air tight capsule they came with milk spots on the obverse. I'm selling 2 x 10oz 2012 Lunar dragons at this moment.
    So IMO as alluded by others. Milk spots as apposed to silver tarnish expose a flaw in the minting process and usually seen on large and popular runs. (QA goes down the drain).
    I also have 2000/2001 lunar coins. Till this day in capsule. Flawless. I sell these at AUD$60+
     
  8. Pirocco

    Pirocco Well-Known Member

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    A decade silver coin production from dozens Mints, all with a contamination that over time renders coins to ugly scrap, and even no cause identified, let alone a solution. It's just ridiculous.
     
  9. m3sca1

    m3sca1 Active Member

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    First time reading this thread, very interesting to note that after all this time no one seems to be able to find the source of Chlorine ions that are kicking off the reaction. How it is so hidden from the refiners and mints that they can't stop it from affecting their products? For those looking to store their stuff with as little air as possible you may consider storing under inert gas. Long term storage methods use inert gas to push out the air, removing the oxidant Oxygen from the storage container. The topic of PVC and chloride associated with it (which has already been covered on the forum) would have you remove all soft plastic PVC containers from the stash. Also consider paper, cotton wool and other fiber products as potential source of Sulfur compounds. If you have a pool or often use Chlorinated products in the house, you may be the source of your own contamination. Opening your stash after dosing the pool or cleaning the bathroom or even eating a hot mustard sandwich could be the source of a nucleation site for the crystal to start. I do jewelry work and my acid pot (cheap Hydrochloric acid) will tarnish any silver left near it.
    The odor threshold for chlorine is 0.002 ppm in air! I would only take one atom to land on your shiny to kick off a nucleation site. So if you can smell it, and you have a stack nearby that is not 100% sealed, then you could potentially by creating your own problems. I am not making the comments to shift blame from refiners not providing clean silver but just shedding light on what can be done to avoid starting the nucleation. For any hardcore bleach users out there, borax and vinegar is a great alternative.
    And a nucleation site is just that! Once started, no amount of cleaning will ever take away the nucleation site, unless you chemically replace it with something that will take place of the Chlorine atom. Chlorine bonds strongly to things and without substituting the atom, the site will remain a seed point to any other tarnish chemistry that comes along. And if you did manage to get the Chlorine off and not substitute it with some other atom, there will be a pit in the metal that has a charge imbalance, which also is a natural seed point to any passers by. Maybe storing under paraffin oil (like is done with reactive metals such as Sodium and Potassium) is something to consider for ultimate long term storage.
    There is another approach that could be why some shiny stays shiny without us realising why....Germanium.
    I am pretty sure that a lot of 999 stuff out there is a little short of being 999.
    I have heard folks who dissolve gold to make things say 999 gold is more like 960 from bullion bars.
    A little Germanium contamination creates a self healing barrier that prevents oxidation. Look up Argentium Silver.
    I am sure if the mints threw in 1 gram in a kilo per melt that this problem would disappear.
     
  10. Pirocco

    Pirocco Well-Known Member

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    Now that's an approach I never thought about so far. The proneness of modern bullion coins, and some remarkable more relative to others, could indeed be related to the presence of other elements, like that Germanium, that blocks the "milk spot" chemical process.
    Elements that were more present in older silver ore than present.
    Maples have about the worst reputation on this matter, it could be interesting to find out if the Canadian Mint has a specific source of silver that contains less (or not helpful in protection) of those other elements.
    Another explanation may be that Germanium (I just checked) seems to be more expensive than gold, maybe the ore processors extract it specifically, causing the silver "missing" that little amount.
     
  11. m3sca1

    m3sca1 Active Member

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    That makes a lot of sense, certainly if it was not on the radar of the refiner, they would not care to remove it as an impurity.

    here is a price chart from 1950's to the 1990's, maybe good silver comes from a time when the prices are low.
    https://minerals.usgs.gov/minerals/pubs/commodity/germanium/220798.pdf

    here is a snippet from a website I was reading
    https://www.thebalance.com/metal-profile-germanium-2340135
    "History
    Demitri Mendeleev, the father of the periodic table, predicted the existence of element number 32, which he named ekasilicon, in 1869. Seventeen years later chemist Clemens A. Winkler discovered and isolated the element from the rare mineral argyrodite (Ag8GeS6). He named the element after his homeland, Germany.


    During the 1920s, research into the electrical properties of germanium resulted in the development of high purity, single-crystal germanium. Single-crystal germanium was used as rectifying diodes in microwave radar receivers during World War II.


    The first commercial application for germanium came after the war, following the invention of transistors by John Bardeen, Walter Brattain, and William Shockley at Bell Labs in December of 1947. In the years following, germanium-containing transistors found their way into telephone switching equipment, military computers, hearing aids and portable radios.


    Things began to change after 1954, however, when Gordon Teal of Texas Instruments invented a silicon transistor. "
     
  12. Pirocco

    Pirocco Well-Known Member

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    1. Maple Leafs from Canadian Mint have the worst reputation on this milk spot proneness subject.
    2. A Maple Leaf has a property that distinguishes it from nearly all other bullion coins: 9999 instead of 999.
    So, the percentage "other elements" of a Maple is a factor 10 times less than other bullion coins.
    This also supports the theory that other elements may play a decisive role in the presence of those nucleation sites.
    Question: did anyone ever see 90% silver coins (with the other 10% typical copper) with milk spots?
    As far as I know, production of these ceased like half a century ago, the last probably being the French 10 francs 25 grammes 0.900 and larger 50 francs 30 grammes, of late seventies/early eighties.
    I have quite some of these junk coins, and never seen milk spots on them.
    These milk spots have a potential ruining effect on the value of bullion silver, degrading it from bullion to scrap because no sight. Tarnish is just brown>black but milk spots make plain ugly, alike someone peed on the coins.

    When I started to hoard silver, I initially planned to buy only old 90% junk, but it's not easy / time consuming to collect it together in larger quantities so I ended up with mostly bullion, just ordering at any moment at dealer, deliver and done. Reason precisely to have a stack that with a little care can look the same over decades. Bullion is way more demanding, and these milk spots just worsen that even more.
     
  13. SlyGuy

    SlyGuy Active Member

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    Ding ding ding.

    I can sorta understand trying graded coins or low mintages, unique designs, etc on gold coins since gold doesn't corrode much if any... but when silver naturally tarnishes with age? Hmmm.
     
  14. SpacePete

    SpacePete Well-Known Member Silver Stacker

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    ok, I've (hopefully) hermetically sealed some maples and proof Britannias and buried them away. Remind me in several years to disinter them and check with a macro lens for spots.
     
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  15. Dynoman

    Dynoman Active Member

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    It's funny how the RCM describe their silver purity as .9999 & they're easily the worst coins when it comes to Milk spots. I've got some truly horrible examples.
     

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