Just wondering, Do foreign silver bullion coins have milk spot problems like...

CoinHusker

Silver American Eagles do?


I have a yearly set of 1 oz. Britannia's, Maple Leafs, Kook's, Panda's & Libertad's and haven't seen any spots yet but the problems the US Eagles are having has me a bit concerned.

Has anyone seen any spots on theirs yet?


If not, it must have something to do with how the Eagles are processed.

cosmicdebris

I had some on an Australian Proof Chinese Lunar coin. The Perth Mint promptly replaced it with full apologese. Best customer service I have ever seen from a mint anywhere.

CoinHusker

<< <i>I had some on an Australian Proof Chinese Lunar coin. The Perth Mint promptly replaced it with full apologese. Best customer service I have ever seen from a mint anywhere. >>




WOW! Now that is service after the sale. All too often it seems as though a Mint disowns it's products as soon as they are purchased, (or at least 30 days after purchase).

silvereaglecoins

The Aussie Lunars and Kooks almost never have spots, the Chinese Pandas will have a minor spot on about 1 per 100 coins, the Canadian Maples will have spots about 5-10% of the time (depending on the date) and the Mexican Libertads will have spots about 20% of the time (depending on the date). Most common explanation is an "incomplete planchet rinse" at the mint which leaves a residue on the coin which reacts with the mint packaging or PCGS insert later. Here is a 2004 maple, direct from mint packaging:



The silver eagles are plagued by this disturbing problem even more (depending on date). The PCGS holder itself has been know to "turn" perfectly good coins into crap due to some sort of undesirable chemical reaction between the coin and the slab insert, which tends to accelerate the problem.

See my recent thread about milk spots on PCGS ASE's HERE.

wybrit

I've seen the odd spot on a British coin, but nothing like the examples of ASEs in silvereaglecoins' link.

Cruzi

The Australian Kookaburras, Lunar coins and Silver Kangaroos all have the planchets pickled in a mild acidic solution to ensure impurities are removed.


Another factor that may help our coins is they all struck and packaged in an controlled atmosphere, minimising any dust, moisture and contaminants that could affect the coin into the future.

Also not 100% sure on this, but I think our bullion coins are the only ones that come encapsulated as standard practice from the mints, as opposed to many others that do not package bullion at all.

silvereaglecoins

Cruzi's explanation about the Aussie coins makes perfect sense. They are far and away the highest quality bullion coins and almost never have spots or problems. The Chinese pandas also come with a "mint capsule" but are double sealed in a PVC pouch. If the internal capsule is not sealed real tight, PVC haze will develop over time. The Canadian maples and UK Britannias come sealed in mint mylar (phylo film) which tends to discolor or get brittle with age. Finally, the Mexican libertads and American eagles come in 20-coin rolls (cardboard and polystyrene plastic respectively).

The best solution for long term storage is probably an acetone rinse, followed by a distilled water rinse, then into a direct-fit air-tite (no ring).

CoinHusker

Thanks John! A wealth of good information.