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 Replies: 73 / Views: 47,021 |
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Bedrock of the Community
United States
20753 Posts |
Quote:
When you remove a coin from acetone, you can expect it to be dry before you manage to place it on a surface. It evaporates that fast. However note that the amount of humidity in the air where your at will make a difference. I've found in very humid areas it will evaporate very slowly compared to dry days. Also, evaporation times vary pending movement of air. In other words if you have a fan moving the air, Acetone will evaporate faster. However, using Acetone near electrical devices is not smart. To play safe with the usage of Acetone, simply use the Search tab at the top of the page here and type in Acetone, coin cleaning, cleaning coins, etc. |
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Moderator
 Australia
16827 Posts |
You will see differing opinions on whether or not to give a "final water rinse" to coins after cleaning with acetone.
In part, this is because not all acetones are equal. The lab grade stuff I use is pure and uncontaminated. But commercial-grade acetone is often "denatured" by adding denatonium benzoate, to make it taste terrible and thus discourage anyone from either accidentally or deliberately drinking it. Although DB is harmless to coins (and a thin layer of DB on a coin might actually be useful if you have small children or dogs that are in the habit of swallowing things), not everyone is happy at the concept of deliberately exposing their coins to it.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Valued Member
 Canada
125 Posts |
Wow this thread has more information now than I originally was hoping for! This is wonderful :)
Another question about acetone... since it removes organic material from a coin, would this include any smudging on a coin from finger oils or other greasy/oily substances? I know it won't remove any permanent markings do to prolonged exposure of said oily substance. But if it is fresh?
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Moderator
United States
188342 Posts |
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Just keep an eye on your skin and apply some type of moisturizer after you're done handling your coins. Good advice.  |
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Moderator
United States
188342 Posts |
Quote:
Another question about acetone... since it removes organic material from a coin, would this include any smudging on a coin from finger oils or other greasy/oily substances? I know it won't remove any permanent markings do to prolonged exposure of said oily substance. But if it is fresh? Yes, it will work for a fresh print. As you have stated, it will not undo any damage caused by the print. |
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Valued Member
Canada
125 Posts |
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Moderator
United States
23522 Posts |
For the record, Sap, the proportion of Denatonium Benzoate in acetone is on the order of 2cc's in a 55-gallon drum. Effective concentrations are well under 10ppm.
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Valued Member
Canada
125 Posts |
Just an update on this, I did some tests on discard coins that I was going to return to the wild.
For nickels and pennies, I put some fresh fingerprints on some coins and allowed them to soak for a bit to see if the oil came off. To my surprise, acetone did nothing to remove the fresh fingerprints. I had to scrub hard (I know this is a no no but they were test coins) with a Qtip to remove the prints and even then, you could still see some residue.
I found with pennies that have a dark brown patina that the acetone gives the coins a sort of orangey brown look that is very unpleasant to the eye. Not sure how I feel about cleaning some of my older coppers in acetone now... Maybe it had something to do with the fact they were not pure copper coins?
Finally there were a couple pennies and nickels that had some gunk on them that I was sure the acetone would take off. Some of it came off when I rolled a Qtip over, some would not so I scrubbed harder to no avail.
In conclusion, I was actually very disappointed in these trials. From this first test acetone 1) ruins the color on brown pennies, 2) does not remove fresh oil and 3) does not really remove much gunk from coins.
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Valued Member
Taiwan
192 Posts |
I'm just curious, how long did you let the "fresh" fingerprint sit for?
Yesterday I cleaned one on a nickel-plated steel coin, the fingerprint was totally gone for good. The fingerprint was maybe an hour old.
Also, from my experience, sometimes having your acetone to evaporate too quickly is not a good thing.
Evaporation needs heat, so it "sucks" heat from your coin, making it cold. I live in a tropical country with a hot and humid air. Sometimes, the cooled coin has water condensed on it.
To prevent this, I quickly put the coin between 2 cotton pads and hold it on my hand to keep it warm so no water gets condensed.
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Moderator
United States
188342 Posts |
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I found with pennies that have a dark brown patina that the acetone gives the coins a sort of orangey brown look that is very unpleasant to the eye. Not sure how I feel about cleaning some of my older coppers in acetone now... Maybe it had something to do with the fact they were not pure copper coins? Interesting. I have never experienced this before. |
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Valued Member
Canada
125 Posts |
Hey Guybrush,
In terms of the fingerprint itself, it was on the coin for maybe 30 minutes? I let one coin in the acetone for roughly 3 minutes before taking it out and another for 10. I assumed that would have been long enough.
I cleaned the coins in my shop and I live in Canada so it was a good 5 degrees celsius (41 fahrenheit) which is pretty cool. I didn't expect the acetone to evaporate as quickly as it did but I guess it is really dry right now!
jbuck. Maybe I need to run some more controlled experiments. Maybe the brown that came off was more grime then a patina and therefore showed patches? I am not sure :S
I think I will run some more tests before putting my collectible coins to the test. I don't have anything that most people would consider remotely valuable to, but money is really tight so every dollar counts for coins I have already :)
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Moderator
United States
188342 Posts |
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jbuck. Maybe I need to run some more controlled experiments. Maybe the brown that came off was more grime then a patina and therefore showed patches? I am not sure :S That would make sense. |
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Bedrock of the Community
United States
17884 Posts |
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Do a final rinse with fresh acetone. Do not use canned air, let it air dry (acetone evaporates fast). Using fresh acetone is important so no particulates are left behind when the acetone evaporates. And to make sure any traces are removed, make that final rinse a FLOWING rinse (pour fresh acetone over the coin, not dipping it into a bowl of acetone.) Quote:
"Green ick" on a coin could be a manifestation of PVC plasticizer reaction, or it could be Bronze Disease (verdigris). Could also be old skin oils and dirt. Acetone will remove that easily. |
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Valued Member
Taiwan
192 Posts |
@arvan hmm maybe copper reacts with fingerprint oil that fast.
I still remember a copper chunk (not a coin) that I brasso'd when I was younger. After becoming bright pinky, I touched it quite a lot for a while and it became dull brown again overnight.
What about the nickel you mentioned? Perhaps it also reacts rather quickly because nickels are 75% copper?
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Valued Member
Canada
125 Posts |
That could be an idea guybrush but the cent was a modern one. I guess the copper plating would be enough to have the oils react? It's pretty frustrating that the acetone really did nothing but I am going to try a few other things and see what happens. I am going to try and do an acetone pour after the bath and see if that helps.
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Replies: 73 / Views: 47,021 |
First Page
Posted 11/20/2017 12:20 am
