Acetone - Light Green

lilolme

I had some acetone in a pickle jar that I occasionally used the last several months on a single coin or similar.

I finally decided to clean up some mostly raw foreign coins that had been stored in those PVC soft flips for years, and this many years ago.

There are probably a couple hundred so coins and I put about 1/3, maybe 60, into the acetone in the pickle jar. Was going to check it the next day but it turned into two days. This is what I found. (Forgot to rotate the image but you get the idea)

Wow! That was a lot of PVC.

For those jumping to let me know that the coins still have some PVC on them due to all the residue in this acetone - Yes I know. Will do a 2nd soak but I have at least two more initial group soaks to do first.
.

.
PS - I won't be re-using this jar. It is much easier (and safer) to clean out a new pickle jar than this mess.

gumby1234

Are you sure that's not pickle juice.

lilolme

@gumby1234 said:
Are you sure that's not pickle juice.

.
That is exactly what I thought. It looks like pickle juice. But as I stated in the OP, this acetone was in this jar for months (literally) and was clear. After putting these 60 or so coins in and coming back to it a couple days later the color had changed. These are some ugly looking coins.

I just tried to get a picture of the next page in the binder. Actually was able to get some of it on the first try. This does not come close to showing it all because when you tilt the coin or page around one can see more. Notice the green on the edge of the coins (they all have it but only seen in the picture on some). Also remember some of the brown seen is also PVC. I will see if it happens again.

gumby1234

I'm sure it will happen again with the amount of coins that you put in that have pvc on them.

LanceNewmanOCC

gratz. you just acetoned more coins in one fell swoop than i EVER have total.

ricko

Wow... That is one hellacious mess..... Might take 3 or 4 soaks to get really clean. Cheers, RickO

lilolme

@LanceNewmanOCC said:
gratz. you just acetoned more coins in one fell swoop than i EVER have total.

Agree. I just more than doubled what I had done before. And now can see why I kept putting this off. Outside of the silver ones these are mostly what might be called 'spenders' I would guess.

lkeigwin

I don't recall which forum member posted the following method a while back. But I like it, especially when treating a lot of coins.

Fill three glass jars with acetone.
Dip in jar-1, then rinse in jar-2.
Then a final rinse in jar-3.

After removing the PVC from a handful of coins toss the acetone in jar-1.
Then Jar-2 becomes jar-1, jar-3 becomes jar-2 and a new fresh jar-3 is created.

This assures a nice, safe final rinse.
Lance.

lilolme

That sounds like a good way to do it and particularly for something with a little importance.

I am just trying to get the years of PVC flip cleaned up a little on these miscellaneous foreign coins. I put it off long enough but will probably put the second soak off like I did the first one. Hey they at least look okay now. Picture below as I dumped them onto a paper towel to dry. That is just a 2x3 carpet piece.

Oh and I know people are wanting to know but yes the second pickle juice (soaking) is being created now. About ready to do the 3rd jar also. Was interesting to see the acetone color change as I was not expecting it.

Namvet69

I also see that my acetone bath slowly loses it's clarity as coin debris sloughs off. Most drops to the bottom but some remains in suspension. Acetone is cheap so I change it often. Good luck. Peace Roy

lilolme

Well another unexpected result. I had two new jars, put the coins in and filled with some acetone. Let them sit about 1 1/2 days. These had a few more coins and probably not as much acetone (guess since jar is larger diameter). Both of the new jars turned blueish. I poured the two jars into one a took a picture with what is left of the original green one. Then a picture of the two groups of coins drying.

I will mention this is a new can of acetone and the first was a different older can. Both from Lowes.

.

browntrout

Very interesting process!

Mr_Spud

The blue suggests some copper sulfate based verdigris came off of one or more of the copper coins, possibly. Careful or you’ll end up making the copper ones turn pink from stripping off the surface “skin”

lilolme

@Mr_Spud said:
The blue suggests some copper sulfate based verdigris came off of one or more of the copper coins, possibly. Careful or you’ll end up making the copper ones turn pink from stripping off the surface “skin”

Thanks for the info. I was wondering about the blue. I did notice a couple of the copper ones looked a little different. I will go back and double check them now.
I am putting the pages back together now. It is actually looking okay. Something worth glancing at occasionally.

Smudge

Distilled water final rinse.

Sapyx

Copper sulfate usually isn't a major component of verdigris. Copper sulfate is water-soluble, and you can't fix verdigris just by washing your coins in water. Verdigris is usually a combination of copper chloride and copper carbonates. Such inorganic salts, of the kind formed by normal environmental corrosion, will not dissolve in acetone. For acetone to turn green or blue like that, some more interesting chemistry is happening.

"PVC damage" is not caused by PVC directly. By itself, PVC is completely inert to metals. The problem is that "by itself", pure PVC is brittle and not transparent, so you can't make coin album pages out of it. But PVC is nice and cheap, so people still try to use it to cut costs. To make PVC soft, flexible, and transparent, they need to add plasticizers to it. Since cost-cutting is the whole point of using PVC, you obviously want this plasticizer to be as cheap as possible, while still doing the job.

The most common "cheap plasticizers" for PVC are phthalic acid esters, or "phthalates". To make phthalates, you start with phthalic anhydride, add an alcohol of your choice, and a little bit of sulfuric acid for a catalyst. The "alcohol of your choice" will largely determine the properties of the plasticizer, and the resultant plastic. For coin album pages, you need an alcohol with between 4 and 14 carbon atoms in the molecule, so ethanol (regular drinking alcohol) with only two carbon atoms won't cut it. The excess alcohol is boiled off during the process, but the acid remains behind in the resultant liquid and goes on to become embedded in the plastic. While the process chosen for any one specific plastic product is typically shrouded in patent secrecy, diisononyl phthalate (DINP) is the one most commonly used these days in non-food-based applications of PVC. These phthalates are oily liquids at room temperature, and like any liquid will slowly evaporate over time - evaporated phthaltes in the air are the source of the "vinyl smell" from new shower curtains.

Over prolonged contact with metal, especially in the presence of atmospheric moisture and especially if pressure is applied (like the album getting squeezed by a bunch of other album pages full of coins sitting on top of it), the phthalates and any residual sulfuric acid will slowly leach out of the plastic, and stick to the surface of the coin. There, the acid reacts with the raw metal on the coin's surface, then the phthalates react with the dissolved metal. The sticky goo that comes off your coins is therefore mostly composed of unreacted phthalte, with the colour coming from metal phthalates - organometallic compounds, which are soluble in acetone.

But the final colour of your used acetone will depend largely on the composition of the original coins being soaked. The blue would therefore be copper phthalate; the green is more likely to be nickel phthalate, or perhaps it's blue copper phthalate mixing with yellow-brown iron phthalate extracted from steel coins. I do not know the chemistry well enough to know if silver phthalate will form; I suspect not. Back when PVC was a major problem in the coin industry in the 1970s .999 silver coins hadn't been invented yet.

heavymetal

How do you dispose of the used acetone?

lilolme

I did a second soak with smaller batches and just enough acetone to cover the top of the coins. The acetone did not change color this time except one might have had a slight green tint.

Okay I got five pages filled out (a little under half way done). I bought new pages (so no PVC in these) and I did not use any flips as these just did not seem worth it. Problem is some want to slid out of the page holder when flipping pages. But I think I can put this 3 ring on the books shelf (and not buried in a box) and maybe look at it occasionally. That is what the coins are for aren't they.

The copper looks okay except a couple. One is that Australian penny but not sure how bad it was to start. A couple silver ones still have some crusty green. Might soak them for a long time but it may be permanent.

I won't bore you with this anymore but just thought I would give the update.

PS - I see @Sapyx add a lot of good information while I was typing this. Thanks.
Almost all of the flips had that nasty ring of death where the coins had been for years, and some had markings into the center of the ring or points on the coin.

Mr_Spud

@Sapyx is right about it probably not being copper sulfate unless there is some water present. I double checked just now and it’s not soluble in pure acetone. But it’s some copper compound to look that blue.