PVC Residue On Coins

Arizona Coin Collector

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Feb 22, 2009, 11:53:27 AM2/22/09

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FROM:
http://www.bellaonline.com/articles/art60942.asp

PVC Residue On Coins

Polyvinyl chloride damage is caused by storing coins
in soft plastic flips that contain polyvinyl chloride
(PVC.) PVC generally manifests as a light-to-dark
greenish residue, although it can appear as milky or
light grey in color. It has a distinctive "plastic"
odor which can range from subtle to strong. I
recommend treating coins for PVC residue whenever you
can smell PVC on them, even if you do not see the
greenish residue yet, because if the coin has a
plastic smell, the PVC decomposition process has begun.

Difficultness: Easy

Time involved: around 10 minutes, including
preparation and clean-up time.

Here's How:

1. Put on latex gloves and eye protective cover. Be
sure you have good ventilation, and avoid utilizing
the kitchen or any area wherever an open flame is
present. Acetone is a potent chemical that is highly
flammable. Although acetone does not burn the skin
(it is a cardinal component in many nail polish
removers,) you should avoid unnecessary contact.

2. Pour out a very small amount of acetone into the
container. (Do not use plastic as acetone will melt
it.) You only need about 1/4 to 1/2 ounce if you
use a small drinking glass, or tiny jar. You need
only enough to cover the coin by about 1/4 inch.

3. Gently put the coin with PVC residue into the
dish, and swirl the acetone around for about 30
seconds. If both sides of the coin are affected,
turn it over and swirl the other side.

4. Remove the coin and allow it to air dry. If
the PVC residue is still present, continue with
Step 5. If the coin is clean, go on to your next
coin, and when finished dispose of the acetone
by pouring it into a resealable jar. Never pour
acetone down a drain, or let more than a very
small amount evaporate. Acetone is considered
hazardous and must be handled appropriately.

5. If the coin still needs additional cleaning
after swirling (and in my experience, most do),
take a cotton swab (such as a Q-Tip) and dip it
into the acetone. (Do not use cotton swabs with
plastic sticks!) Then, using a firm and steady
hand, roll the swab across the coin's surface
on the PVC-infected areas, taking care not to
employ any kind of rubbing or abrasive maneuver.
If the coin has a lot of PVC residue, you should
replace the swab every few "rolls." Keep rolling,
using new swabs as required, until the coin
looks clean, and then swirl it again to finish.

Tips:

1. Never rub the coin with the cotton swab. Apply
only rolling movements. The slightest abrasion
may cause hairlines to the coin's surface.

2. Occasionally PVC residue can be stubborn and
won't respond to rolling. Try soaking the coin in
a sealed jar of acetone for 24 hours before
undertaking the rolling maneuver again. If rolling
still fails, attempt additional intensive,
higher-pressure "swabbing" (but don't "scrub!") If
the PVC residue still does not respond (in other
words, if the swab Is not picking up anything at
all,) your coin might not be cleanable (or
perhaps it's not PVC residue that you see on the
coin.) You could try sending it to NCS for expert
preservation.

3. To prevent future PVC damage, don't store your
coins in soft or flexible plastic flips. Use the
more rigid Mylar flips instead. Never store your
coins in any sort of plastic containers that
have a smell.

What You Need:

* Full-strength acetone (sold where paint supplies are found)
* Small glass or metal dish (PVC melts plastic!)
* Coin with PVC damage
* Latex or rubber gloves
* Protective eye-wear
* Cotton swabs (such as Q-Tips)

..

Mr. Jaggers

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Feb 22, 2009, 12:07:14 PM2/22/09

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Arizona Coin Collector wrote:
> FROM:
> http://www.bellaonline.com/articles/art60942.asp
>
> PVC Residue On Coins
>
> Polyvinyl chloride damage is caused by storing coins
> in soft plastic flips that contain polyvinyl chloride
> (PVC.)

The damage is not caused by the polyvinyl chloride itself, but by certain
chemicals that are used to impregnate the PVC to break up the polymer
structure and make it softer and more pliable. At one time there was a
poster here who took issue with that statement, saying that even
unadulterated PVC can create damage, but even if it can, it takes a very,
very long time to manifest itself. The "green slime" results from that
plasticizer, not the PVC. Once the slime migrates out of the PVC and
touches the coin, it causes irreversible damage. Under those conditions,
the only thing that can be done is to wash away the slime and hope that the
surfaces have not been completely destroyed. But surface damage always
occurs to some degree, and often in a very short time. We can hope that
such coins never see the inside of a slab, but alas, they do.

James

MKW

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Feb 22, 2009, 5:34:05 PM2/22/09

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Can damage occure from say storing a complete packaged US Mint product
in a brand name ziplock bag? Coin itself is sealed in its original
capsule and box.

Or storing slabbed coins in the small ziplock bags?

Mr. Jaggers

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Feb 22, 2009, 6:07:20 PM2/22/09

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It has been demonstrated that neither mint packaging nor slabs are airtight.
Over time, air inside both can slowly exchange itself with air outside. If
there is any contaminant associated with the ziplock bags, well, need I say
more?

There are special carboard holders available, called InterceptShield, into
which slabs can be inserted, with cutouts that provide a view of the the
coin. They are also available for mint sets as well. I know nothing about
this vendor, but here is some info on the boxes themselves:

http://www.wizardcoinsupply.com/products/intercept-shield-boxes/

James