The blessing of PVC, or "The cost of carelessness"
shirohniichan
Posts: 4,992 ✭✭✭
I've come across a few coins on bid boards that look deceivingly bland. They don't have the luster or "pizzazz" of choice coins and receive few bids. The problem with them is that they have a light haze caused by exposure to PVC.
For me, the buyer, it is a blessing in disguise. If the PVC encrustation looks new and mild enough, a quick swab with MS70 will remove it to reveal great luster. Of course, if the PVC has been on there a long time, removal of it will show dull coin surfaces that look like raw aluminum (on silver coins). There are times when it's a gamble-- the coin may turn out nice or damaged, and one won't know until he takes the PVC off.
If you are selling coins, be sure to check for PVC haze. If you're not skilled in its removal, talk to someone who is and see what can be done. If you don't, you could leave a lot of money on the table. Your coin that looks like a washed out AU coin that nets an EF grade may actually be an AU-55 with light PVC haze. For certain coins that makes a huge difference in value.
On a side note, I was unhappy to receive a few lots of coins with PVC on them that were not so described in the auction catalog. Two coins turned out to be really nice, and one copper turned out to have the green death on it. Fortunately, it was one of the least expensive coins in the lot. The blessing was that the coins sold for less than 60% of retail, so the potential buyers who looked at them may have judged them to be worse than they actually were. Had the consigner or auction house removed the PVC, I'm almost positive they would have garnered a higher hammer price.
For me, the buyer, it is a blessing in disguise. If the PVC encrustation looks new and mild enough, a quick swab with MS70 will remove it to reveal great luster. Of course, if the PVC has been on there a long time, removal of it will show dull coin surfaces that look like raw aluminum (on silver coins). There are times when it's a gamble-- the coin may turn out nice or damaged, and one won't know until he takes the PVC off.
If you are selling coins, be sure to check for PVC haze. If you're not skilled in its removal, talk to someone who is and see what can be done. If you don't, you could leave a lot of money on the table. Your coin that looks like a washed out AU coin that nets an EF grade may actually be an AU-55 with light PVC haze. For certain coins that makes a huge difference in value.
On a side note, I was unhappy to receive a few lots of coins with PVC on them that were not so described in the auction catalog. Two coins turned out to be really nice, and one copper turned out to have the green death on it. Fortunately, it was one of the least expensive coins in the lot. The blessing was that the coins sold for less than 60% of retail, so the potential buyers who looked at them may have judged them to be worse than they actually were. Had the consigner or auction house removed the PVC, I'm almost positive they would have garnered a higher hammer price.
Obscurum per obscurius
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Comments
This is extremely good advice! I have to confess to having received PVC bodybags from PCGS where I completely missed the PVC -- novice as it may sound, I thought the coins had slightly dull luster -- even with quite close examination, there was no obvious residue, it was really only apparent in the luster. After an acetone dip, the coins came alive, and were slabbed!
Part of my PCGS correspondence course!
I bought a somewhat scarce coin with a value of $65 in EF and $105 in AU for only about $45 because of PVC haze. I gave it a bath when I got home and found it to be a nice coin.
Obscurum per obscurius
If the PVC hasn't been on bronze very long, it comes off with no noticeable trace (at least when using a 5x loupe). If the PVC or green corrosion has eaten into the surface, the affected areas appear as dark spots on red copper. In my experience the acetone rinse at the end leaves the copper with a purplish hue, and the corroded areas turn gun-metal gray.
Obscurum per obscurius