Stubborn PVC?
thevolcanogod
Posts: 270 ✭✭✭
I have a WL Half that has what I thought was PVC - there's lots of little green dots all over the surface. However, I've soaked this coin in acetone for going on 3 weeks with pretty much no change in the dots. They won't even push with the corner of a flip. I've heard PVC can be stubborn sometimes but this is getting ridiculous. I would like to add the coin to my set but not like this.
Pics - the PVC shows up as black spots in the scope but it's actually emerald green in the loupe.
Am I mistaken and this is not actually PVC? Anyone have PVC take over 3 weeks and not budge? Any suggestions?
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Could it be corrosion? The silver is alloyed with copper which is reactive to moisture. Unless it's a rare or valuable coin I'd try some coin dip such as E-Z-Est or Tarnex.
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It could be copper corrosion (verdigris - which shows as green) as PerryHall suggested. Try using a rose thorn...Be aware, you may not like what the surface looks like once it is gone.... Cheers, RickO
The probability is high that the PVC -- or corrosion, it doesn't matter -- has begun to eat into the coin. If the coin isn't too valuable you could also try to work at the spots with a round, wooden toothpick, either dry (hard) or wet (softer) -- not everyone here may agree with using a toothpick, but I do it all the time to remove verdigris, especially from tight spots, and it works fine as long as you are careful. I would then follow up with acetone to gently clean up the area. If that doesn't work it's probably time to trade this WLH for a better example. Good luck!
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Thanks for the tips - I’ll try the thorn/toothpick route. I guess I didn’t take into account that it may be corrosion in the alloy metals. It’s not a hugely expensive walker but it’s nicely struck and has great luster.
If it's no longer green... Once it"s gone black there's no coming back.
A wooden toothpick won't hurt the surface of a coin if you soak the tip in mineral oil and place another drop on the coins area your picking at.
You don't want to go at it dry as both need to be lubricated.
I just logged onto a desktop to see this better. Acetone is a quick fix as if it's still green and your patient soak it in mineral oil for another 3 weeks. Mineral oil will remove PVC just as acetone. After 3 weeks take it out all oily and place it on a few napkins. What you want is really oily so the napkins soak and there's no rubbing to the lower side. I usually place a plastic shopping bag under the napkins as the oil will soak through. Then again with oil atop the coin soak a toothpick and with a loupe and good lightning see if you can budge the PVC by either gently taping on it or giving it a slight nudge from the side. There's no picking action as your gently trying to push it off the surface. If it hasn't eaten into the surface and it's not pitted it should come off. If some is stubborn but other spots came off stop and re-soak in mineral oil again for a few more weeks as there's no forcing it off by applying pressure. A Q-Tip also will not hurt a coin if both are soaked in mineral oil. As far as the rose thorn is concerned it's a joke as it's either too soft when green and too hard and brittle when dried out. Buy toothpicks with a blunt tip not pointed. Since it's silver you can degrease it with another acetone soak. Good Luck!
I would try some MS70. It has taken stuff off for me that acetone wouldn't touch. Try not to get it get on your fingers though, it's caustic.
Collector, occasional seller
SOAK IT IN MS-70 FULL STRENGTH. ACETONE is a great chemical; however, from my experience conserving coins it is OVERRATED and a VERY SLOW "fix" that often (as you have proved to yourself) does nothing. It has its place. As others have posted, little black spots as these may have etched the surface under them already.
I have soaked gold coins in acetone or xylene and the pvc doesn't just come off, you need to use a Q tip under the fluid surface to carefully get the substance off. I don't know what magic solution NCS uses, probably has something to do with better chemicals and temperature differences.
I know it's not silver and not sure how it would react, but I have a FEC that has verdigris on it. I got rid of a lot of it by soaking it in olive oil for a few months and then picking it off with a toothpick. It still has a little on it but looks better than it did.
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