Cleaning Coins (Proof-Mint only)
Your coins may lose their brightness over time, and you'll be tempted to polish them. The best
advice is ... DON'T.
Any cleaning will begin to wear and scratch the medallion surface, and, though it may look
brighter for a time, the medallion will lose its brilliant proof-mint finish.
The natural tarnish of a medallion is expected by collectors, and is actually proof of its
authenticity.
Storing Your Coins (Proof-Mint only)
Air. Exposure to the air oxidizes metal, changing its color. This does not reduce the value of
your coins. It is advisable though, if you are storing your coins for a long period of time, you
store them in a controlled environment.
Environment. A relatively constant, moderate temperature and low humidity are preferable for
long term storage of numismatic collectibles. Placing packets of silica gel in coin storage
areas helps control atmospheric moisture.
Holders. Several types of "containers" for coins are available. Be sure to source near airtight
holders made of inert materials to ensure your coins have a long shelf life.
For Proof-Mint coins packaged by Medallic Hawaii, many come encapsulated to protect the
coin from damage. Do not remove the coin from its capsule.
Paper envelopes of various sizes are sometimes used for one or more coins. Be sure to use
envelopes made explicitly for holding coins, or your coins may change color (tone) over time
due to reaction with sulfur or other chemicals present in the paper.
Various brands of folders and albums are sold for series and type sets. When properly used,
they offer some protection from wear and handling. Over several years coins may tone due to
reaction with sulfur or other chemicals present, and they are therefore not a good choice for
long term storage of higher grade coins.
Plastic flips are available in various materials. "Soft" flips are made from polyvinyl chloride
(PVC) which decomposes over time with disastrous results for coins They are therefore not
suitable for long term storage. Mylar and acetate flips do not contain PVC. However, they are
hard (may scratch the coin if not inserted and removed carefully) and brittle. While not airtight,
they are reasonable choices for moderate value coins that will be "left alone" for multiple
years but less so for coins to be shipped or that will be removed and reinserted.
Mylar-line cardboard, often called "2x2s" but also available in other sizes, are similar to plastic
flips. A coin is placed between the two halves, which are then stapled together (some brands
contain an adhesive).
Tubes are plastic containers designed to hold a number of the same size coins. They are fine
for bulk storage of circulated coins and can be used for higher grade coins, provided the coins
do not move. A disadvantage is that the coins cannot be viewed without being removed from
the tube.
Hard plastic holders are preferable for more valuable coins. They are not known to contain
any materials that harm coins and offer good protection against scratches and other physical
damage. They are available for individual and small sets of coins.
"Slabs" are sonically sealed hard plastic holders for individual coins. They offer good (though
still not perfect) protection, but because of the expense of having a coin slabbed, they are
generally suitable only for more valuable coins.
