PVC and Acetone - A detailed Step-by-Step Pictorial Guide

[physics-fan3.14]

Recently there was a series of questions regarding the use of acetone to conserve PVC afflicted coins. A number of people expressed concern and interest in the methods used to remove PVC from coins using acetone. When I first performed this procedure, I was rather nervous about it myself, concerned that I would damage one of my coins. But with a little reassurance, and practice on a cheap coin to get familiar with it, anyone can perform this very simple and very important conservation.

 

My roommate recently asked me to go through his small collection of coins and catalogue, appraise, and conserve those that needed it. Among them, I found this 1850 large cent, and realized that it would be perfect for an informative thread.

 

Before we proceed, I recommend everyone not familiar with PVC and its affect on coins to read my WYNTK article on the subject.

 

Alright then, let’s get started. Acetone is a volatile compound, but safe when used properly - in a well ventilated area away from sparks and flame sources. When I'm dealing with it, I usually crack a window and turn on the ceiling fan. If you've ever smelled fingernail polish remover, then you know exactly what acetone smells like, as the two are the same thing (don't use fingernail polish remover on your coins though - usually it has extra perfume or dye or something to make it appealing to the ladies). You need pure, 100% acetone, and should be able to get a quart of it at Wal-Mart for only a few dollars.

 

As I was going through my buddy’s collection, I noticed several of his coins were in very old plastic flips, and that some of them were growing green spots. There were three things that alerted me to the presence of PVC: 1.) The green spots. 2.) The plastic felt soft, pliable, and slightly slimy. 3.) The flips (and coins in them) had a faint smell that reminded me of a new shower curtain. This is a great diagnostic, since many shower curtains are made from PVC.

 

The holder, with coin removed. Notice the bright green film on the inside of the flip, where the coin was contacting the plastic.

 

 

Before pictures of the coin. Notice the reverse was far more seriously affected than the obverse. There was still a film on the obverse, but not nearly as bad. The reverse had a very thick film which was literally obscuring details. I was somewhat nervous about this, I was afraid that the PVC might have already started eating into the surface of the coin. If this happens, the damage is irreversible. But, removing the PVC and preventing further damage is still necessary, in my opinion.

 

 

So, I got a glass and put about a half inch of acetone in the bottom, and gently set the coin in. I would recommend not using anything with dyes or plastics, because acetone may ruin these. A clear, shallow glass or porcelain bowl is the best. Also, make sure that you set the coin in gently, to avoid splashing or damaging the coin. I would also recommend doing this over a paper towel, and not over a surface you care about much. I once spilled a couple of drops on a wooden table that was varnished. One use of acetone is to remove varnish, and the spot on the table was stripped. So now I do it at my cheap particle board desk, where I don't care if there are spots or scratches. Anyways, here is the coin in the cup of acetone:

 

 

After letting it soak for a few minutes, I pulled it out. Acetone is perfectly safe on the skin, although I wouldn't recommend washing your hands in it regularly. But fishing a coin out won't hurt you. It will feel very cool to the skin because acetone evaporates very quickly. This is the same basic principle why you sweat - the evaporation cools you.

 

Perform this next operation over your paper towels, because you don't want to damage the coin if you drop it. Take a Q-tip, dip it in the acetone, and gently wipe the surface of the coin. Q-tips are soft and absorb well, and shouldn't damage the coin unless used too roughly. Dipping the Q-tip in acetone will also help to minimize friction, and will allow spot removal at the point of contact. The acetone will evaporate from the surface of the coin very quickly, and will evaporate from the Q-tip rather quickly as well. When the head of the Q-tip begins to dry out, just dip it back in the acetone again. As you wipe the PVC from the coin, the Q-tip will become green. When you see it green, or possibly brownish, just replace it. See below for what I'm talking about. The top Q-tip was only used briefly, but the PVC was so thick on this coin that I had to replace it. You don't want to continue re-using the same Q-tip because you don't want the PVC removed to be deposited back on the coin. You also don't want too much of it to be re-dissolved into your acetone as you are dipping the head to relubricate it.

 

 

Keep wiping (gently) until the Q-tip no longer turns green. If there is still PVC on the surface of your coin, just set it back in the acetone for a little while longer. Depending on the thickness of the contamination, it might have to be there for a long time, and you might have to repeat numerous times. For this coin, I had to repeat many times: I used about 25 Q-tips over a period of three days and three changes of acetone. After a little while of soaking and wiping, I noticed that the acetone the coin was sitting in started becoming cloudy. It also began to diminish in effectiveness, so I poured out the cloudy acetone and replaced it.

 

 

Be careful that you don't leave the coin in the acetone overnight, unless it’s well covered and there is plenty of acetone in there. I made this mistake and woke up to find all the acetone gone, and much of the PVC that had dissolved in the acetone had been redeposited on the coin. There was a thick film of slime all over the bottom of the coin. Luckily, this PVC was not bonded strongly with the coin, and so came back off quickly.

 

About halfway through the process, you can see noticeable improvement:

 

 

So, after a couple dozen Q-tips, three or four changes of acetone, 4 days, and probably over an hour total of wiping, dipping, and examining, this coin was salvaged. I was quite pleased with the results; it turned out to have not been damaged by the PVC. I managed to rescue a decent looking, albeit well circulated, large cent. This was by far the worst contamination I had ever seen, but it turned out well.

 

 

So, if you have anything else you would like to point out, I welcome your comments. Conserving your coins is important - you wouldn't want your Picasso to be hidden under dirt and grime that would damage it. Likewise, you don't want your coins, no matter how common, to be hidden under PVC that will eat holes into them. This is an important function as we are only temporary holders of history - there have been numerous people who have owned this coin before us, and there will be many more people to own this coin after us. It is our responsibility to make sure that it lasts in good condition!

 

[Schatzy]

Thanks Jason.......Great Post (thumbs u

[brog]

Jason, Does this not hurt the grading of a coin. Or does it not hurt the field of the coin. For i have a couple that has pvc on them an i was planning on sending them to NCS for conservation.

Ron

[physics-fan3.14]

No, removing PVC with acetone will not hurt the grading of the coin. If the PVC has eaten into the surface of the coin it will bag, and if you submit directly to NGC without removing the PVC, it will quite understandably bag. However, if you submit a PVC coin to NCS, they will most likely just use acetone themselves on it and charge you a whole lot. If you are concerned about it, by all means submit to NCS, but it is a simple process. Just try it on a cheap coin first to get the hang of it and see exactly what needs to be done and to gain confidence. You can take a cent from circulation - that will give you an idea of exactly how much pressure you can use on the Q-tip without harming the coin.

[prudden]

I've done this to a few coins as well after being assured by many experts it was harmless. It does no harm to luster,color,toning or grade.But, the only problem is on uncirculated coins,you can't rub with a q-tip.The best you can do is agitate the acetone over the affected area. Even light rubbing will leave tell-tale hairlines.I thought of using a very,very fine artist brush but I haven't tried it yet. If someone knows differently please chime in.I'd like to know too.

[Bugmann1974]

Thank you very much for the lesson! I will probably be trying this out soon.

 

I did find one typo in there though.....

 

If there is still PVC on the surface of your coin, just set it back in the PVC for a little while longer.

[physics-fan3.14]

Oops, fixed

 

I haven't had the problem you speak of prudden - try it on some high grade cents from circulation to get an idea of how much pressure you can use.

[prudden]

Oops, fixed

 

I haven't had the problem you speak of prudden - try it on some high grade cents from circulation to get an idea of how much pressure you can use.

 

Noted.Thanks

[bsshog40]

Good job Jason. I've used acetone to remove scotch tape from coins been have never been that diligent in trying to remove pvc. Good going!

[jesbroken]

Great post, Jason. I've used acetone many times and always with excellent results. I'm getting ready to try it on some old buffaloes. I'll remember to do before and after pics this time.

Thanks again,

Jim

[James_OldeTowne]

I MUST applaud this as being one of the finest posts I've ever seen anywhere!

 

SUPERB JOB!!!!!!!