The original comment is a load of PCGS inspired nonsense. Acetone or Koinsolv is used all the time to make sure your coin DOES get graded for fear of coming back PVC contaminated . Question , being a bit of a Devils advocate. I wonder in future say 60 years or so down the road when most of us on here are pushing daisies, if the plastic holders of the PCGS and NGC services will contaminate the coins that were graded? Hmmmm.
Thanks for Good Info. And Happy Easter to those who participate
It was PCGS that he said that had the sniffer.
I tend to believe the folks on this forum that it leaves no trace, as I have used it for years cleaning sheet metal and I told the LCS gentleman about the acetone when he came up with this statement. It didn't sound correct to me either.
That's why I trusted that you folks here would blow that statement out the window.
PCGS has the sniffer, it is used on coins submitted under the Secure Plus level. Basically what it is is a gas chromatograph. The coin is rinsed with a volatile organic solvent (such as acetone) which dissolves contamiants off the surface of the coin which are then sorted by molecular weight. The results are compared to a set of standard test substances to determine what substances were on the coin.
Acetone being extremely volatile does not remain on the surfaces of the coin (not to mention the fact that it might also be the carrier solvent they use in the machine!)
Acetone alone will absolutely not keep a coin from grading.
Acetone is extremely volatile. At or near STP, it vaporizes and diffuses into the air at a rapid pace. Notice how when you have a dish of acetone, it evaporates quickly if uncovered? On the exact same premise - even if you were to not rinse the coin at all after an acetone bath - by the time you took the coin from the bath, packaged it, and mailed it to PCGS for analysis, there would be no trace of the solvent left on the surface at all. Pure acetone doesn't leave any sort of residue that would enable detection.
Also, even if they *could* detect that a coin has been treated with acetone, that still wouldn't be grounds for details grading. Acetone baths are considered market-acceptable handling. As such, that means the coin will grade. Details grading is only used when the coin is considered damaged by market standards. Removal of dirt in a way that does not affect the coin's surfaces (e.g., an acetone bath) and, in many cases even dipping, are considered non-damaging and won't result in a details grade even if they're noticeable.
N.B., this all goes out the window if you do something else to damage the coin. Any sort of wiping will still result in an improper cleaning designation, so don't rub the coin dry after an acetone soak, don't use a cloth to remove "stubborn" dirt, etc. Soak it, rinse it, and either carefully blot dry or let air-dry.
edit: And Conder's answer above is right - acetone may well be the mobile phase in their GC/MS. Even if not, it's almost certainly used in the maintenance/cleaning of the instrument.
There are many "sniffer" based detection devices available. In another life I installed Trace Detection equipment in airports throughout the States and beyond. The technology of Ion Mass Spectrometry can detect any molecular substance by ionizing the molecules with an isotope (Nickel 63 is the most common) and then comparing to whatever you load into the machine's look up tables. I know that at least one of the manufacturers uses acetone as the carrier for its dopants. As an aside, coins I have submitted to the TPG's previously dipped/"cleaned" with acetone, MS70, and/or EZest have all made it through the grading process problem free. EZest bears the greatest risk though, so very short dips and copious amounts of water afterward with it are safest. PG
Since acetone does NOT affect coin surfaces it will NOT affect the gradeability of a coin.
Alcohol is a bit different and I'm less familiar with its use. Rubbing alcohol (isopropyl) from the drugstore is not good since it's only about 75% pure. You need the 95+% stuff but then it will melt plastic.
I don't know much about ethanol or methanol but what little I do know suggests avoiding them. Although ethanol at your local "watering hole" makes you feel MUCH better ;-)
I've watched the PCGS grading video (What happens to my coin) or something like that. 3 numismatists "grade" the coin independently using nothing more than a light & magnification. If a consensus isn't reached a 4th person is used. Your buddy is pulling your chain.
The PCGS video is reassuring, however, I do wish that they would use gloves, especially on red briliant proof bronze coins!
I still like to inspect in hand, any coin that I am considering to purchase. That makes it essential for me to grade any coin for myself, be it modern, medieval or ancient.
If your coin is just dirty will acetone clean it? I do have coins that are in pretty good condition but they are dirty, oily and sort of nasty looking. Will acetone clean off that gunk? How does having a dirty coin affect its grade. It is definitely unappealing to see a dirty coin even if it is in otherwise fine condition. How do you tell if it is just dirt and grime as opposed to an injury to the finish when you see a coin you want all things else being equal?
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Posted 04/04/2015 8:39 pm
