I'm going to try to post one coin each day about something fun. Feel free to add to the thread with something related. This is a fun story. About 25 years ago, the IRS had an auction at a local storage place. They set up chairs for about 60 or 80 people and most of the seats were full. It was a nasty cold rainy day. There was a lot of really nice high dollar art and furniture in each container. One of the lots was a small plastic bag of a hand full of silver half dollars. There were several Kennedy and Walker half dollars in the bag. They would not let you open the bag but I spotted a Barber in the group. I waited in the rain for hours for the lot to come up and bought it at less than the price of silver at the time. Sorry about the first images but that's the best I could do back in those days. Notice the green tint to the coin. That's the early look of PVC. After a few acetone baths it went to PCI but still came back in a problem slab. At some point, I cracked it out and gave acetone a try again. Probably still won't grade but that's ok. The last images give you an idea of it's look today. Please join in with your images of the looks of PVC.
What a great, clean looking Half!! Bummer on the PVC, it would still make a great Type coin! This is my best Barber coin, a Dime I've posted previously
Sorry... a mere rookie in the presence of those with wisdom... Questionn removing the pvc damage, how would I use these chemicals the portions to the mix, soak time, rinse with water... Mahalo in anticipation of your sage advice...
Acetone is a solvent and shouldn't be mixed with anything, but be pure. The soak time doesn't matter much since you are just dissolving contamination, an hour or so, changing a few times. Distilled water rinse is optional.
I wanted to say more about your great post. You nailed it. Each bath will carry away more of the contamination. I also feel it's important to bring up that there is a difference between PVC contamination and PVC damage. If you catch it and take care of it, in time, there is no damage. It's best to take care of it as early as possible.
I follow the adage of my mom, "like dissolves like." Since PVC (polyvinyl chloride) contains chlorine, it only makes sense that a chlorinated solvent would remove it better than a non-chlorinated one.
I believe the “like dissolves like” saying has more to do with the polarity of what you’re working with and not the actual chemical composition. Molecules’ structures can cause there to be regions in the molecule that have a slight negative charge and a slight positive charge. This imbalance (or lack thereof) causes a molecule to be polar (or not). The oxygen in acetone and the chlorine in PVC each have unpaired electrons, causing both of them to be somewhat polar. Evidently they’re of similar polarity since acetone is able to dissolve PVC. Something like hexane would be so much less polar than PVC that it couldn’t dissolve it. Likewise, something very polar like water would be too polar to dissolve PVC.
From experience, I have found better results with MeCl2 than acetone - especially with copper. No unexpected color changes. And I don't know where the avg person can get residue-free acetone (99.99%).
Here is one I picked up years ago stashed it away in a 2*2 flip and found it the other day. This coin was not affected visually when I bought it. It had evidence of a previous corrosion, but I was too young a collector to understand what it was.
