Proper acetone procedure

Lets get this coin a thread of its' own, and see if we can fix it before you submit it. Verdigris is a slow killer, but it's a killer all the same, so we should show concern for the next owners down the road. Numismatics done right is an altruistic avocation.

 

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Okay

 

I originally learned how to do it from here: http://coins.about.com/od/caringforcoins/ht/pvc_damage.htm
But, just in my opinion, I find it works better if you soak the coins first.

 

I sold that barber dime awhile back.

 

My understanding is that anything other than pure acetone will leave spots and possibly damage the coin. That means no nail polish remover.

 

Ok here's a different question: I washed a bunch of coins in "Dawn" and they tarnished. Among them were some clad Eisenhowers. I was so upset I did a one second dip in Tarnex. Did I "doctor" the coin? Or did I just fix a toning problem that occurred because of me washing the coin's in soapy water?

 

The Tarnex didn't "doctor" the coin, it trashed it.

 

I've not seen soap and water or Dawn tarnish a coin before. I'll need to see if I can repeat what happened to you. Tarnex is a little harsh to use on coins. We don't actually know if they are "trashed" w/o seeing the results.

 

One quick addition- there are two basic kinds of 2x2 plastic flips, the soft PVC and the stiffer mylar. If you store a coin for a long period of time in a PVC plastic flip the coin can get a greenish film on it. acetone will remove that without harming the coin.
I personally only put raw coins in capsules and then into flips.

 

...if you catch it very early. That green color is from metal that's being dissolved by acid. Acetone will take away the stuff that's generating the acid, but it won't restore the dissolved metal.

 

I'm not a chemist, but I've cleaned many coins that were stored in the old PVC flips over the years and I only found a film on the coin from the PVC that acetone cleaned off; I have never found any damage to the coin under the film. I will research this, but I believe the PVC flip just leaves a film.

 

You mean like this?
https://proxiblog.org/2013/11/27/some-pvc-damaged-coins-can-be-cleaned/

 

I read your link and it refers to copper coins. Simply exposing a copper coin to air can cause it to turn brown and in a humid climate water can cause corrosion problems. When I lived back east I used to put a moisture absorbing cartridge in with my coins, here in the southwest that's not necessary. I guess I should have said I have never seen a PVC (*poly vinyl Chloride) flip that creates a film hurt a coin, except for copper coins.

rim's cents, does that make you feel better? There are ways to add to a person's answer that is not rude or "clever". I belong to several forum's and this is the only ones where people seem to enjoy sitting on the side and waiting for a chance to snipe someone. You made a valid point, but not in a very nice way. Anyone with any coin collecting experience knows that copper coins are the hardest to keep in their original condition, even the TPGs have red, red/brown, and brown to describe the color of copper, the only metal, that they list a coin's color. The example you show above still has the PVC damage so how the author lists parts of the coin still covered by the PVC green film as damaged, without removing the film, is beyond me.

 

I am glad I made you feel better. Now try this thread and you can get a 2fer on your forms - https://www.cointalk.com/threads/pvc-damage-how-to-remove-it.289196/

 

All I read, at the link you included, was back to this coin form and it had several posts that disagreed with each other on PVC and acetone treatment. Instead of putting in links, why not take the time to give your own opinion. This post started with a newbie asking about acetone, replies addressed that question, until your four word answer and a link. This is why newbies are afraid to participate in discussions or ask questions on this forum. I get PMs all the time, because they are afraid to post out in the open for fear of ridicule.

I have been a collector for over fifty years, but I learn things I didn't know from this forum many times, I would like it to open up to new collectors so they can learn from the many experienced and knowledgeable posters to this forum.

It is just as easy to be decent and polite as it is to be snarky and look for errors in what someone posts. Correct them, but do it in a civilized way, that's how we learn.

To put it simply PVC flips(soft) bad-Mylar (hard flips) good. Capsules, and to some degree, cardboard 2x2s, better, and I know this is a topic of considerable discussion, but the best way is to send it to one of the big four TPGs for slabbing.

 

Please research. The ultimate byproduct of the PVC plasticizer reaction is hydrochloric acid, and that's not "just a film." If you've dealt with long-term storage in PVC flips without seeing etched coins, you've been very lucky. Many of us haven't been so lucky.

There remains much disinformation out there regarding the topic - for some reason - so the more often it's discussed, the better.

 

I'll quote- from Wikipedia:
Polyvinyl chloride (/ˌpɑːlivaɪnəl ˈklɔːraɪd/),[4] more correctly but unusually poly(vinyl chloride), commonly abbreviated PVC, is the world's third-most widely produced synthetic plastic polymer, after polyethylene and polypropylene.[5]
PVC comes in two basic forms: rigid (sometimes abbreviated as RPVC) and flexible. The rigid form of PVC is used in construction for pipe and in profile applications such as doors and windows. It is also used for bottles, other non-food packaging, and cards (such as bank or membership cards). It can be made softer and more flexible by the addition of plasticizers, the most widely used being phthalates. In this form, it is also used in plumbing, electrical cable insulation, imitation leather, signage, inflatable products, and many applications where it replaces rubber.[6]
Pure poly(vinyl chloride) is a white, brittle solid. It is insoluble in alcohol but slightly soluble in tetrahydrofuran.

I don't see hydrochloric acid mentioned and I don't think it would be appropriate in the uses listed above, if it was present.

 

The plasticizer used in PVC is usually one of the phthalates which are oily chemicals that get between the polymer chains of the PVC and cause them to slip over one another. Plasticizer leakage on coins should cause an oily, gunky film that could pick up almost anything from anywhere and hold it against the coin. Now if the PVC gets REALLY old or gets damaged from sunlight or heat, the PVC itself can degrade giving off HCl gas. If the gas is dissolved in water (hard to get away from) we call it hydrochloric acid. Now, this is all just bookish chem stuff, and I usually don't argue too much with old-hands in collecting who have seen a lot.

 

That's why chemistry is so interesting. Over time, PVC will degrade and form hydrochloric acid. A very strong mineral acid that will eat copper, silver, nickel, etc. Most coinage has traces of copper in it, that is what causes the greenish/blue color, the coin being eaten away. Even with a thin film of PVC, some metal has been removed. The damage only shows itself when it has removed enough metal to dull the surface.

 

Again, I'm just an old-time coin collector (with a BA and MA in Biology, not chemistry) but you gave a lot of IFs- IF the PVC is very old, IF the PVC is exposed to sunlight (I don't keep my coins out in thee sun), IF the PVC is exposed to water (again, I don't expose my coins to moisture let alone water), IF the PVC picks up anything from anywhere (that's why we keep coins in flips, capsules, etc.), IF the PVC degrades it can (not will) give off HCL gas, IF the HCL is dissolved in water (again, I keep my coins away from moisture) it can form Hydrochloric Acid. TO many IFS.

Let's just agree that a coin that has a layer of PVC film on it has little to no worth, so trying a bath in acetone is a no lose try. If it works, you've got a good coin, if it doesn't, you're back to where you started with the PVC film.