Archival Question on Plastic used by US & Foreign Mints

Planchet

Lets talk about coins packaged by the mint and how safe the packaging being used is for the coins. You can comment about copper, nickel, clad, silver etc. I am intellectually interested in this issue and the issue of I the archival characteristics of different plastics used to package coins by the US Mint and Foreign Mints.

What led to this question is that I happened to be at a B&M in the process of selling off my collection. For the heck of it (and without intending to purchase anything) I asked to see the Uncirculated Gold Buffalos in the Mint packaging. The plastic seems fairly pliable. I have also asked to see and handled the plastic encased Canadian Silver Maple Leafs. Both of the mint plastic packaging for these items seem very pliable and I was interested to know whether they are safe for long term storage or whether the plastic used contains PVC or softeners.

Again, this is an academic question, as I have no plans to purchase these items. I have always had a keen interest in archival issues as my wife is an avid scrapbooker and I have had experience with archival issues regarding document preservation.

Stuff I have seen from the US Mint such as proof sets come what appears to be a poly styrene holder. Ploy styrene has a reputation as a fairly inert plastic. However some of the items I have seen have other softer plastics or paper inside them.

I guess the big question is what do you know and what has been the experience with mint packaging and its effect on coins, whether they be copper, nickel, or silver, new issues or old issues. I want to learn from your experience.

Thanks

Planchet

ricko

Planchet... I cannot contribute greatly to your research... however, I will add what I have seen. Older mint issues in the cello (not sure of composition) packages (inside yellow envelopes) seems, after years, to impart toning to nickles and occasionally other coins. I do not know if the composition has varied, but the toning does. The plastic holders for eagles and buffalos seems to be inert as I have seen zero changes on my coins... and I have them since issue in 1986. The silver, proof and uncirc sets in the hard plastic containers with inserts have so far, not toned either. All this having been said, I do believe some people have had different experiences. Your research will be empirical, but interesting.... there may also be some outside influences on some of the holders. Cheers, RickO

Planchet

"..... Your research will be empirical, but interesting.... there may also be some outside influences on some of the holders. Cheers, RickO >>

"

Thanks Ricko

yes, it is empirical but this forum has alot of members that can contribute. As to outside influences. the ambient air in which the sealed coins are held may make a difference. Things like humidity, pollution, proximity to salt water, may effect the coins even when sealed in plastic. Many types of plastic allow some degree of air migration. In addition, although there may be a seal, in many cases it is not a perfect seal.

Plachet

cladking

'68-'81 mint set holders are not suitable for very long term storage. They
have an inner layer of plastic which has PVC. it is especially bad for cents
and some dates like the '69.

tmot99

Soft plastic does not necessarily mean PVC or anything else bad. Mylar is flexible, moldable, and inert. That's not to say that the film on the gold Buffaloes is safe or not. I have not tested it, so I do not know it's content.

Mercury10c

I had several Silver Maples that I left in the RCM plastic for about 5 years. I've noticed no
issues with the coins. I don't know if 5 years is long enough for PVC to leech out, but my
standard procedure now is that if I buy silver bullion coins in mint plastic, I remove them
and place them into a Sure Safe Coinvault.

Planchet

Never mind this comment. Found my answer on the web.

cladking

The very worst holders used by a mint are probably the 1975 Japanese mint
set holders. These were seeping onto the coins almost immediately and by the
early '80's mant of the coins were irretrievibly damaged. Today it is very difficult
to find one of these sets with any coins that can be salvaged. Despite the high
mintage of the set some of the coins in it will prove quite tough in unc and poss-
ibly scarce in high grade.