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hazelman

Using acetone to clean coins

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It would be interesting to know what all these various solvents DON'T have in common?

Meths

Acetone

Surgical Spirits

???

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Metho is ethanol plus a small amount of methanol plus sometimes purple dye.

Surgical sprit is similar without dye.

While acetone is an aromatic ketone and is the smell on your breath when drinking alcohol.

All are solvents that remove grease etc, and probably not a lot between them when cleaning coins.

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Metho is ethanol plus a small amount of methanol plus sometimes purple dye.

Surgical sprit is similar without dye.

While acetone is an aromatic ketone and is the smell on your breath when drinking alcohol.

All are solvents that remove grease etc, and probably not a lot between them when cleaning coins.

Interesting, thanks, Oz! Any idea what happens to the purple dye when the solvent evaporates?

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A good question. For the most part metho is clear in Australia. However I do have a bottle or mauve colored metho which I applied to a paper serviette. To start with there was a slight mauve color which disappeared as the spirit evaporated. The

paper is now clean. So I guess it isn't a problem perhaps the dye evaporates along with the spirit.

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A good question. For the most part metho is clear in Australia. However I do have a bottle or mauve colored metho which I applied to a paper serviette. To start with there was a slight mauve color which disappeared as the spirit evaporated. The

paper is now clean. So I guess it isn't a problem perhaps the dye evaporates along with the spirit.

The purple dye used is called Methyl Violet and is a triple benzine ring molecule. As such it isn't going to evaporate quickly as its basically a solid at room temperature. However, pretty much all solids have some sort of natural vapour pressure, so it may well disappear over time. In the meantime, however invisible it may be, you will still have a slight purple layer on your coins. I'd avoid dyed meths if at all possible.

Edit: Just noticed that Methyl Violet is green in powder form, so expect a green tinge to your coins, not purple. Also, the dye is quite soluble in water, so having removed any fingerprints etc. with meths, you can rinse off under the tap and that should then remove the residual dye. Of course, if you then drop it down the plughole........

Edited by DaveG38

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A good question. For the most part metho is clear in Australia. However I do have a bottle or mauve colored metho which I applied to a paper serviette. To start with there was a slight mauve color which disappeared as the spirit evaporated. The

paper is now clean. So I guess it isn't a problem perhaps the dye evaporates along with the spirit.

The purple dye used is called Methyl Violet and is a triple benzine ring molecule. As such it isn't going to evaporate quickly as its basically a solid at room temperature. However, pretty much all solids have some sort of natural vapour pressure, so it may well disappear over time. In the meantime, however invisible it may be, you will still have a slight purple layer on your coins. I'd avoid dyed meths if at all possible.

I think I would too!

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Anyone know if industrial methylated spirit will do the same job? Can borrow work supplies

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Anyone know if industrial methylated spirit will do the same job? Can borrow work supplies

Not sure, Charlie, to be honest? Having found acetone does a brilliant job I've never ventured further. Also, a quid's worth of acetone will easily do 50-100 coins, so it's always been cheap enough to use anyway. :)

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Don't panic.. Just remembered got gallons of acetone too, use it every day without thinking.

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HMMM ... just my opinion from the other side of the pond. Acetone being a ketone is good for say removing that stickiness that originally developed in alot of those coin holders which had PVC.

In terms of silver and gold is there really a need to clean these alloys? In terms of copper there is probably three good materials: Verdi-Care, Xylol and JPL Coin Care. The last being my invention and derived from the original coin care formulation using flurocarbon chemistry products. Originally Freon TF was used which was originally ban on commercial products due to its effect on the ozone but is use is different in the commercial sector.

I normally do not like acetone on copper as prolonged dwell times creates a drying out effect or at times a whitening of the surface (i.e., dry out effect).

Verdi-Care is good for preservation, xylol for long dwell times of tough copper oxides which go deeper into the coin and the final product for light surficial verdigree of copper oxide (i.e., typically seen initial green film.

John Lorenzo

Numismatist

United States

johnmenc@optonline.net

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Hi John,

Speaking for myself, I'm not really talking about 'cleaning' in the traditional sense. I'm more referring to decontamination, which is mostly about removing acid greases, etc. If I find there's a dirty black cotton bud at the end of it, so much the better. :)

CuNi and 500 silver is also appreciative of a degrease too IMHO!

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Any time a chemical comes into contact - in particularly with a copper coin surface its some form of cleaning. All three cleaners (Verdi-Care, Xylol & JPL Coin Care) have one thing in common a nuetral pH. Indeed solvents like isopropyl alcohol, keteon, actone, methyl ethyl ketone are nuetral solvents but other than xylol most can turn a surface whitish through dry out.

Decontamination is just another word for soil removal. I agree acetone is cheap and plentiful but if necessary its best to use one of these materials IMO. I have heard of complaints of the high shipping of Verdi-Care to the U.K. and I sell my product only to fellow collectors who are either desperate or who I have known for awhile. I use chemicals no longer available on the open consumer product.

But we can argue in circles. Anyone who wishes to try it I can send them a bottle. There was another topic in terms of toning. The two main contaminants in the open air which tone coins are chlorides and sulfur. A book William Weimer on Coin Chemistry does this subject very well and this is confimed on some BNJ and RNS metalluricial studies from guys like Craddock and Northover. One trick I used is taking sulfur gel which is used by Afro-Americans as a hair product. It contains a large amount of sulfur - apply a small dab inside a paper envelope and let the coin sit in there for a year.

There was some comments that a cleaned coin may never properly retone. Its false. Its works pretty well and to achieve rainbow toning stick a silver coin wrapped in aluminum foil in a toaster oven for 400*F for 30 minute intervals. Try it.

Understood - you can't remove surface hailrlines if its part of the cleaning process - obviously. Carbon spots can't be removed from copper proofs and copper spots on gold coins need to be left alone.

last night I spoke to the largest group of metal detectors in the East Coast of the U.S. - ironically - but it was interesting. yes - I did recommend these (3) products. Yep - acetone came up again. I would use it only to remove that sticky surface from a copper with a QUICK q-tip application. Agree ... just to be clear ... other than ground burial why would anyone decontaminate a silver or gold coin?

John Lorenzo

Numismatist

United States

johnmenc@optonline.net

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I'll get my coat, then! :)

I Q-tip everything with acetone, and have never seen a white-out, yet!

Anyway, all that aside, thank-you for the info.

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> I very carefully 'mop' the coins using cotton buds, which have been saturated in acetone

> I normally do not like acetone on copper as prolonged dwell times creates a drying out effect or at times a whitening of the surface (i.e., dry out effect).
Hi everyone. I'm a newbie here, and to coin collecting in general, but i do have some chem lab experience.
Rather than use a cotton bud, my inclination would be to use a squeeze bottle with a narrow nozzle to apply the acetone and a can of compressed air to remove the solvent. This would allow better control of the extent and duration of the 'wash' process.
As mentioned, the problem with acetone is that, as well as being an solvent, is an effective dehydrating agent; if the acetone is allowed to penetrate the deeply ingrained organic gunk on the surface of a coin, the dehydration process can irreversibly discolour the organics.
To minimise the dwell time, quick rinses / squirts with a liberal amount of acetone followed immediately by air drying would be more effective method to loosen surface grease and remove it from metal surfaces than prolonged ‘mopping’ or soaking.
That's not to say that the dehydrating property of acetone can't be useful. In a manner of speaking, water ‘dissolves’ in acetone. If a coin has been immersed in water, it can be thoroughly dried by means of a quick squirt of acetone followed by a blast of air to evaporate the solvent - a lot more effective than mechanical means and kinder on the metallic surfaces too.

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I very much like the simple approach of using acetone immersion and buds of cotton to get rid of the ?gunk/organics? and then rinse with dish soap and water, then with more water and tamp down on high nap white cotton towel...

Edited by VickySilver

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I very much like the simple approach of using acetone immersion and buds of cotton to get rid of the ?gunk/organics? and then rinse with dish soap and water, then with more water and tamp down on high nap white cotton towel...

Egyptian or Indian cotton Vicky?

:lol:

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I like the idea but, in reality, both the coin and my fingers are bone dry long before I'd get any chance to rinse OR blow-dry the coin, it evaporates that quickly.

I don't treat acetone too seriously to be honest. It will remove a lot of gunk you may have thought you were stuck with but, and more importantly, it also degreases coins very effectively, hopefully ruling out any future print or unevenness of tone.

Every little helps, as Azda (or is it Tescos?) would say! :)

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I've tried Acetone on a couple of gunky copper coins and it did the trick, getting the worst of the dirt out of the incuse bits and from around the detail, which is what I wanted. I didn't notice any adverse effect on the coins but neither was exactly BU to start with.

I also attempted to remove what I thought was marker pen from a hammered shilling. Didn't shift it at all, so I guess it must just be odd toning (maybe it lay for years on some string or leather cord?) ... unless Acetone doesn't work the way I thought it did. Anyway I don't fancy dipping the coin, so I'll just have to live with it.

:unsure:

Edited by TomGoodheart

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Egyptian cotton the best, but really not that important. Acetone does not seem to remove India ink or similar marking. I also use ammonia - carefully - on copper with the same rinse technique.

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Hi All

My first post and new to coin collecting. I have a 1856 half penny that has what looks like a fingerprint on the reverse. I have tried acetone but no no joy in removing it.

Any help or advice on getting rid of it would be appreciated.

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Finger prints you have to live with unless you get the brasso out. :o

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Hi All

My first post and new to coin collecting. I have a 1856 half penny that has what looks like a fingerprint on the reverse. I have tried acetone but no no joy in removing it.

Any help or advice on getting rid of it would be appreciated.

They only tend to show on coins with good lustre so assume unless its got hold of the coin and is really dark its a nice coin.

Have you got a picture ?.

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I do have a picture, but cannot figure out how to paste it onto the page. Looks like I need to create a URL?

Do you know if there is a guide somewhere on the site that tells me how to do it?

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Ian, save the image to your computer and then when you are typing there should be a 'More Reply Options' button on the bottom right. Click it, then you should get taken to a new page which has the option to add an attachment near the bottom.

As long as the file is under 500kb then it should upload fine.

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Thank you, that was nice and easy. Hope it looks okay when you view it?

post-8965-0-51411200-1449505837_thumb.jp

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