Did the plastic used in the 70's mint sets contain PVC? Second does anyone have pictures of what PVC damage looks like on modern clad coins? I've seen it on coppers, but never clad.
The US Mint sets were not in PVC package. However, the mint sets of the same era from Japan were sold in PVC laden packaging and these coins are oftentimes found ruined with a vivid greenish slime adhering to the surfaces.
US mint sets were packaged in four layers of plastic up until 1985, I believe. The outer two layers are a hard and safe plastic but the interior two layer don't appear to be safe. They are very soft and very thin. Many coins in these sets are being ruined and collectors should take steps to save those which survive. It's already too late for the 1968-P penny as 100% of these are ruined. Most are pretty disgusting and only 7% look half dewcent and all of these have small carbon spots as well. The clad and nickels are affected differently by date. Worst are the '69-D quarters which turn a very unattractive and mottled grey. The '68 quarters turn dark but aren't too unattractive. '71 to '84 clads aren't as badly affected but the pennies can be pretty bad in a few cases. 1984-D one cent coins are going the same way as the '68. Post-'84 mint set packaging appears to be OK and is not composed of layers.
I have also noticed the poor quality of cents in the 68 and 69 Mint Sets. Please expound on the packaging, King. Are they not inert? I have a nice set of Mint sets in OGP and I want to keep them in tact without ruining the coins if possible.
There's not a lot to say really except that the inside layer of plastic is extremely thin, extremely soft, and burns with a green flame. I assume it has the harmful plasticizert in it. The grading companies do return some mint set coins as being ungradable because of this plasticizer being on the coins. I don't know for certain that it was used up until 1984 but there is no apparent change in it until the mylar came out in 1985. The first years of the mint sets you'll sometimes have these plastic layers delaminate and on rare occassion a whole outside sheet will peel right off. This is might be caused by a prolonged exposure to high moisture enviroment but I have little confidence since it is so rare. The early mint set years are far more affected than later ones and this isn't solely caused by age since the earlier dates have been degrading at a fairly constant rate for much longer than the later dates. It's not solely caused by packaging either because the problem varies between dates and denominations. I have stabilized a few of the '68 cents by soaking them in alcohol since even before they all started going bad and this is only mostly effective. There appears to have been something in the minting and planchet handling process that is the primary source of the problem at least for the '68-P cent. These coins were washed and dried before being sealed but I would think the alcohol would be 100% effective if the problem was with this process. A lot of the later Ikes turn dark and some of the nickels get problems as well. I do still keep some coins in the packaging but I'm not sure this is wise. I do keep air away and avoid temperature changes. I'm counting on my ability to spot problems before they arise but this is very risky. I lost all my '69-D gem mint sets a few years back because they suddenly turned. This is still heartbreaking and '69-D is one of my favorite dates. The individual coins cut from these sets are still mostly OK and the stabilized coins are OK but I lost all twenty of the gem sets. I now consider all mint set packaging highly suspect until proven otherwise. A lot of the foreign sets are simply attrocious and the coins will be completely ruined if left in them. The mid-'70's Japanese packaging and mid-'60's French are among the worst. Some of the Russian sets are main contenders and as a rule of thumb you should never allow coins to come into contact with foam rubber. If it is then stabilize it and holder it. So many of these moderns were rare even before they went bad because they didn't appear in mint sets and now a lot of mint sets are going bad. Collectors really need to pay more attention to how coins are packaged before and after they acquire them. There are so many high quality protection systems available now days but perhaps never before have there been so many horrible ones as well.
Thanks for all this valuable information cladking...one question and it maybe nothing more than your opinion but I'd like to hear it anyways. Question: Did the Mints knowingly provide packaging material for the Mint Sets that would eventually degrade and ruin coins, or were they oblivious to possible plasticizers being used in their packaging material? I know the Mints purchased the machines to heat seal the flat packs, along with the rolls of pilofilm, but did they knowingly use these non-collector friendly materials?
I suspect the primary concern was to get the coins out to real collectors as quickly and in as secure of packaging as practicable. I doubt they gave the long term suitability of the materials a great deal of thought but someone likely knew they weren't adequate for long term. I noticed no apparent problem for many years before they started turning. There is so much done exactly the same to each set that even those which show no signs of trouble like the 1986 might have trouble in the future. Normally the problems should appear in sets stored under the worst conditions first so there should normally be a warning. I believe most of the more modern US packaging will prove good for long term storage. Some of the problems are independent of the packaging and a function of the way the coins were made or processed before they were packaged or even before they were minted. Keeping an eye on them and good storage is important. There are a few packaging materials that I suspect were designed to injure coins but I doubt any mints used packaging with the intent of damaging them. Most mint sets are composed of either specially made or specially selected coins. It just doesn't make sense that they'd want to diminish these in any way. Watch out for privately made folders, albums, and holders though. It seems the softer it is the more likely to cause problems. Look for airtight and try to store coins in good conditions including low humidity and constant temperature.
Not all of the '68 P Lincolns are ruined. The one in my set that I've had for about ten years now is still hanging in there. It has just a few spots that you can only see with a loupe. I store my sets in my walk-in closet with dessicant. I think it's the most stable place in the house as far as humidity and temperature. I do have other sets where the lincolns have gotten worse over time so I'm not sure it's just a storage issue either. I really don't want to take the coins out of the set to try and preserve them, I like to keep my mint sets intact. I guess the only thing is to hope for the best. Here's my '69 &'69's
