Do modern silver commems get milk spots like SAE's do?
CoinHusker
Posts: 5,034 ✭✭✭
We all know of the problems slabbed SAE's have with milk spotting, but I have never seen a thread about the same problem on slabbed modern silver commems. Does any one know if this is a problem? If not, why not?
Is it due to a different composition of the coin? Are they processed differently?
Curious minds want to know.
Thanks
Is it due to a different composition of the coin? Are they processed differently?
Curious minds want to know.
Thanks
Collecting coins, medals and currency featuring "The Sower"
0
Comments
<< <i>This speckling is often seen on a few modern proof issues. >>
.......................especially during cold and allergy season.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
<< <i>ttown, the "varnished haze" you mentioned, is that just on proof gold pieces or the MS ones as well? >>
I only have a few of the MS $5 coins from the 80's/90's but the ones I've seen have been on the proof and it's fairly common. To me it's not bad looking like the milk spots since it's over the entire coin it's just a different color and a toned look that many don't like but hey most of these are just selling for bullion anyway.
<< <i>This speckling is often seen on a few modern proof issues.
Dear Lord, that looks like a petri dish.
<< <i>I wonder, do only US silver coins develop milk spots? >>
silvereaglecoins postyed this response to a question about the same thing I asked on the darkside a few years ago. I thought his response was interesting.
<< <i>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. >>
If it's a simply organic residues that are being removed (lubricants?), I suppose acetone might be adequate for the rinse. If on the other hand some kind of inorganic salts or oxides are being removed, I would imagine the rinse is a bit more complicated. What's the real deal? ("Coin Chemistry 711" was not an elective in my college days, unfortunately.)