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hazelman

Using acetone to clean coins

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On 9/10/2018 at 9:43 PM, 1949threepence said:

 

 

On 9/10/2018 at 9:25 PM, Ukstu said:

Nothing surprises me anymore .A bit off topic but it just came back into my mind when i read this. 

Years ago i had a mate who i hung round with. We'd been out on the lash and i crashed at his on the sofa. 

I got up in the morning and he was gargling over the sink with Flash multi purpose cleaner. I was like are you seriously gargling with that he was like yeah i always do it mate it clears all the little gremlins out your mouth that you get when you've been on the lash. 

Needless to say we called him Flash from that day on. Life is strange indeed. 

Flash by name flash by nature - queenie liked him a lot LOL

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I've tried a few solvents, notably:

  • Acetone - dissolves most grease based gunge.  It's also miscable with water so you can rinse coins in distilled water if desired.
  • Isopropyl Alcohol - Acetone is better, IMO, but this works.
  • Limonene - This is degreasing agent widely used in cleaning electronics.  It's the orange smelling stuff you use to clean heatsink gunk off CPUs, for those familiar with it.  It works, but it's very, very smelly and has no discernible advantages over acetone.
  • Ammonia solution - Probably the strongest cleaning agent for grease based stains; you can rinse coins off with distilled water.  It won't react with silver or gold, but it will form cuprammonium complexes from copper salts.  I've never tried it with copper coins.

I got a little borosilicate petri dish and lid off Ebay.  This lets you immerse a coin with about 10ml of solvent and pop the lid on it (good for anything that produces fumes).  I also got a 10ml pipette for transfering solvents into the dish.  Usually soaking in acetone and/or ammonia solution for a few minutes is enough to dislodge most gunge and bring the coin up nicely.

One thing I did consider is getting a water pik toothbrush for rinsing and using distilled water for the rinse.

 

Edited by Silverlocks

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don't forget surgical (or methylated) spirit.

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I really don’t think submersion is necessary. On anything but proof coins, a gentle ‘mop’ over the surface with a saturated Q-tip will do! Sacrilege I know, but it works, and even on the finest fields, reflected under natural AND artificial light, you’ll perceive no difference…dig out your 1967 pennies and see for yourself.

The one thing I would say, however, and I shared it on here a long time ago…never re-dip your bud into the acetone, otherwise, by the end of the bottle, you’ll be layering more junk onto the coin than you’re taking off! 

Edited by Coinery
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I have never tried anything apart from acetone with a cotton bud. (And I will probably not try anything else). For me it is very good in dissolving a range of things such as grease. It is more volatile than the various alcohols (due to lower boiling point) and so will quickly evaporate. But I would only consider using it if there is a reason to.

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I am sure this has been mentioned somewhere in this thread but on the occasions when I have used acetone I have found that it leaves an unpleasant iridescence as a residue on bronze and copper.  Similar to the fake toning discussed on other threads.  just my own experiences.  

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1 hour ago, DrLarry said:

I am sure this has been mentioned somewhere in this thread but on the occasions when I have used acetone I have found that it leaves an unpleasant iridescence as a residue on bronze and copper.  Similar to the fake toning discussed on other threads.  just my own experiences.  

I have never had that issue . It has never affected the toning or lustre of any of my copper/ bronzes .I only use it to clean off crud and surface verd, which I then treat with verdicare .I don't soak it and only use a cotton bud .

I know the iridescence you are on about , It may be over vigorous cleaning .More using the cloth /bud to do the cleaning , than letting the Acetone do the work. 

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6 hours ago, DrLarry said:

I am sure this has been mentioned somewhere in this thread but on the occasions when I have used acetone I have found that it leaves an unpleasant iridescence as a residue on bronze and copper.  Similar to the fake toning discussed on other threads.  just my own experiences.  

You’re not using the brands with added moisturisers for cleaning nails are you?

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37 minutes ago, Coinery said:

You’re not using the brands with added moisturisers for cleaning nails are you?

Galvanized nails are far superior. No cleaning required.

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Joking aside, builders merchants sell pure acetone. Probably more sensibly priced than other outlets.

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59 minutes ago, Zo Arms said:

Joking aside, builders merchants sell pure acetone. Probably more sensibly priced than other outlets.

I always got it off ebay - there again postage prices are getting really daft , and they are going up again in april , boo ,hiss my last bottle has 2018 on it thats the manufactureing date

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Local supermarkets still supply it behind their pharmacy counters for around £2…no brainer over getting it posted! 😊

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It might not be legal to post it , being a volitile solvent and all that ....

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A couple of comments, obviously from my perspective (but then again I probably had way too much chemistry, pharmacology, etc.):

Pure acetone not generally a problem and not nearly as toxic as many may lead readers to believe. In the States, we get it at Home Depot for about $8 per quart and that is quite a quantity. It will react on long exposure to copper surfaces.

I recommend it applied with the aforementioned soaked cotton buds or "Q-tips" as we call them on this side of the Pond. Please do not scrub surfaces, and I suggest tamping the surfaces or worst case very light circular strokes sans pressure applied. The cotton on these buds is sometimes not cotton or is of tight wound fibers that are possibly more likely to damage coin surface.

Even after acetone treatment, I wash thoroughly with tap water then apply WITH MY FINGERS and rub into the surface mild dish detergent. I then rinse even more thoroughly and then tamp dry with a high nap white cotton towel.

My favorite solvent, and not just for organics, is the aforementioned ammonia which should be without colorizers or additives if possible. I then do soaks for varying period and use the soaked cotton buds to again work the surfaces in like manner to the acetone. This will reduce some oxidants and not damage the metal on silver, gold or copper nickel but can not guarantee copper and would therefore probably not use it on copper...

There are also the redox tricks which will pull away generally more problematic surface oxidants. Many ways to do it, and experimentation is suggested on lesser coins. One method is to microwave vinegar for 2-3 minutes and then throw in a thin sheet of aluminium, and then baking soda in modest amounts (such as 5 ml/one teaspoon), and then the coin. This one is more fun than the others but have to take care. This REALLY works well on gold coins with those infernal red copper spot oxidations...

 

Blah, blah, blah,,,,,,Anyway, just a couple of points....

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17 hours ago, Coinery said:

You’re not using the brands with added moisturisers for cleaning nails are you?

no just the Care brand sold in the pharmacy I also only use it to loosen fatty deposits with a Q tip 

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On 3/22/2023 at 10:01 PM, copper123 said:

It might not be legal to post it , being a volitile solvent and all that ....

Vendors on Ebay will ship most chemicals that aren't subject to legal restrictions.  If they're dangerous they will come packed in a plastic bag full of activated charcoal.

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I had a half litre of acetone delivered successfully a year or two ago from Ebay.

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6 hours ago, secret santa said:

I had a half litre of acetone delivered successfully a year or two ago from Ebay.

Pretty much everything I've bought I got through Ebay.  They won't ship some stuff - you can buy 32% hydrochloric acid (cleans lime-based mortar stains off brickwork) from Homebase but nobody will ship that from Ebay.  Some chemicals (e.g. Nitric acid) are subject to legal restrictions as precursors to manufacturing things like explosives or narcotics, and you can't get those without a licence, but a pretty wide variety of chemicals are available on the open market and can be ordered and shipped.

In theory, you could do precious metal recovery with chemicals that can be obtained without a licence and mostly purchased online.  Given the fumes, you might not want to try that in a council flat, though.

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On 3/22/2023 at 11:27 AM, DrLarry said:

I am sure this has been mentioned somewhere in this thread but on the occasions when I have used acetone I have found that it leaves an unpleasant iridescence as a residue on bronze and copper.  Similar to the fake toning discussed on other threads.  just my own experiences.  

If you've got a nice shiny new coin you can get a film of gunge left as it evaporates off.  Rinsing the coin in distilled water and leaving it to dry on a clean cloth or some such mitigates this at the expense of it taking longer to dry.  You can get 5l bottles of distilled water off ebay for a few quid. 

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On 3/22/2023 at 10:34 PM, VickySilver said:

My favorite solvent, and not just for organics, is the aforementioned ammonia which should be without colorizers or additives if possible. I then do soaks for varying period and use the soaked cotton buds to again work the surfaces in like manner to the acetone. This will reduce some oxidants and not damage the metal on silver, gold or copper nickel but can not guarantee copper and would therefore probably not use it on copper...

I just bought some ammonia from a chemical supply place.  The bottle I got was really a bit too strong so I dilute it down with maybe 2-3ml ammonia to 10ml distilled water and that works fine.  It won't react with gold or silver - really the only strike against it is that the concentrated solution is very smelly.

Edited by Silverlocks

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Yes, good show and please do report on results. I recently went to first ammonia and then to the reduction method on a Liberia 1965 30 dollar proof coin with great results...

Please do rinse the funk of liberally...

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On 3/26/2023 at 5:18 PM, VickySilver said:

Yes, good show and please do report on results. I recently went to first ammonia and then to the reduction method on a Liberia 1965 30 dollar proof coin with great results...

Please do rinse the funk of liberally...

Next time I get a really grubby sov in I'll take some before and after shots.

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I rather like gold and some good results on proofs with their obnoxious red spotting on some with copper alloys....

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1 hour ago, VickySilver said:

I rather like gold and some good results on proofs with their obnoxious red spotting on some with copper alloys....

The red spots are gold oxide formed through (I think) electrolytic reactions involving impurities on the surface of the gold.  They decompose at 160°C.  If you hunt around on the interwebs you can see videos showing you how to gently heat a coin up with a blowtorch and get rid of them.  I did try this with a sov that had a red spot and it does work.  Just don't overheat the coin.

I used a butane torch of the sort you can buy off Amazon for melting the sugar on creme brulee (should cost about £20 including a few cans of butane), and a jeweller's charcoal soldering block to put the coin on; you can get these off ebay for about 10 quid.

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Hmm, not sure of that and think it is the small copper residual. These chemically reduce in mild redox reactions like the one with baking soda, aluminium and vinegar....

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