Using acetone on copper coins - the scientific result is out

Posted originally in coinpeople, this site shows what happens when you use acetone on copper coins.

I personally never recommand acetone on copper coins and this perhaps is one of the more scientific studies of how acetone acts on copper.

http://www.sunysb.edu/vescalab/research/research7.html

Perhaps that is the best proof why some people get their copped coins ugly toned whereas some don't

 

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Nice article. However, please note that the average, normal, well adjusted individual will not emmerse a copper coin in Acetone for 18 hours and submit it to high intensity lighting. In addition most times Acetone is recommended the recommendor also indicates to only submerse for a very short period of time and then rinse with distilled water and follow that by blow dring with a hair dryer. A person could actually dunk a copper coin in battery acid momentarily and then rinse with distilled water and not much would happen. However, leaving it there for 18 hours would for sure effect the coin.

 

Maybe I am not the best coin guy here.But a little salt and lemon juice will clean copper up

 

Last time I checked, lemon juice contained citric acid.

 

I know that most of you will say "Never clean a coin". So, I don't "clean" my copper coins. I preserve them. Mostly I use a coin cleaner by name "Coin Care" for my copper coins. It does an amazing job on old copper coins. It removes the organic stuff from coin but doesn't touch the original patina and color of copper coins.

Even after few years, I haven't seen any change in the color of those preserved copper coins. Mostly I have used this cleaner on not very expensive coins.

I know a local collector who uses this cleaner on some high end coins and then get them graded by top TPGs. Also, while attending Long Beach Show, I met few dealers who exclusively deal in early large cent and half cent coins. And I have seen them using this same cleaner on their coins worth thousands of dollars. After seeing them, it gave me little extra confidence for using this cleaner on some of mine which needed preservation.

Note: I am just sharing my experience regarding preserving copper coins and am not advocating anything specific. Also, I am not linked with the company in any way which produce this chemical.

Regards
Ballabh Garg

 

I was bored one night ( go figure...look at the toned dime i did a year or so ago) and I dipped a common 1981 cent into taco bell mild sauce. You should have seen it!

It was so pretty and shiny! lol Now I need to figure out how to get the spice flecks off of it lol

 

Actually far more damaging would be the salt used as an abrasive...

 

True, true, true to an extent. However, it should be known that the purity of any chemical greatly depends on the results of any reaction. For example PURE Acetone compared to Acetone purchased in the paint department of Walmart would not necessarily be as pure as the chemical purchased as a pure chemical. Then naturally if any chemical is exposed to one substance such as a Silver or Nickel coin and then used with copper some of the previous metal may be in suspension with the already contaminated Acetone creating the rainbow effect. There is no chemical reason I know of why pure Acetone would rainbow Copper by itself for short periods of time.
As to Lemon juice and salt, again the consistancy of such a solution depends on the purity of the Lemon Juice and the same for the salt. Not only is there an Acid present in a mild form but the salt, if common salt, is actually NaCl and in a solution becomes free ionic elements (Sodium and Chlorine) and can also react with the Copper.
As to dealers cleaning coins and then having them graded by a grading service, anything is possible.
Regardless, cleaning a coin is just dumb. Once done it is done and can't be undone.

 

Lol !

 

Man, now I'm in the mood for mexican lol. Off to the fridge now. Seriously, could you post some pics of it? Would be interesting to see. Back to the original post, I haven't dipped any coins in acetone yet, but have heard sometimes it is neccesary. Like if a coin is horribly corroded, that is neccesary, etc. But I didn't know it could have a chemical effect like that. So I guess there is no safe way to clean or dip a coin, atleast woth out some side effects, either short term, or come later on. My two cents.

Phoenix

 

Just one more episode with Acetone. After reading all this I went out and purchased some Acetone from a chemical supply house in the area. I already have a can of Acetone in the garage that has been there for a few years. Remember that even on the can it states that Acetone will disolve many things and that makes me wonder what is on the inside of the can that would not contaminate the Acetone. The small sample from a chemical supply house was in glass.
I now put the real pure Acetone in a glass beaker, sort of a glass used in chem labs with measurements on them. Enersed 2 Copper coins and left them for about 5 hours in the beaker covered. They were 1983 and 1989 Lincoln Cents. Removed them and really not much change of any kind. Now left a small amount of the Acetone on a concave glass, put outdoors to evaporate. Nothing left on the glass. Now put some of the Acetone from the can from Walmart on that glass to evaporate. Hazy powder left over.
And so that is possibly why some people have poor results from Acetone.
Note these are my findings and numerous other experiments may have different results.

 

Not sure if anyone cares but since I first tried the leave a some coins in Acetone experiment I thought I'd repeat for a longer period of time. Now I can't remember when this post first started but a day or so later I went back and put 3 more Lincoln Cents in a glass with the pure Acetone. Not a lot of sunlight but it has been outdoors for a few days and inside in the garage window for a few more days. Just looked tonight at about 7PM Central time and all 3 coins still look the way they did when I put them in there. I'll take them out in another day or so. Possibly if a person leaves a Copper coin in Acetone for a few hundred years and then layes it out in the rain for a few more it will do something.

 

Nice work.

Personally, I see no need to ever do anything like this with any coin. But it's interesting to see your thinking pattern.

Surely the purity of the acetone is a big factor.

I'm no chemist... but I am a chemical engineer. Acetone is a relatively inert compound with almost no oxidizing potential. And yes, when it evaporates it should leave no residue.

So I don't know what that junky powder is in the Wal-Mart solvent, but I can't see it doing much good for your coinage.

 

I personally wouldn't recommend touching any chemicals.Leave it to an expert in chemistry to help you out as far as getting the verdigris off your coins,especially the Roman coins that sometimes turn up with verdigris.

Aidan.

 

"Coin Care"

In response to Bgarg.
"Coin Care" sounds a lot like Blue Ribbon a cleaner you can no longer get.
I will state that I have no ties to this product and did not when it was available but it had the same properties of "Coin Care".
It was to remove dirt mainly but also left a protective film. I have never been one to clean coins as a rule. However, Blue Ribbon would help a nice coin retain it's patina etc.
When I showed my local dealer my set of Mint State Two Cent Pieces he SUGGESTED using Blue Ribbon to preserve them. He also informed me that he had used this product for years and never had a problem getting PCGS or NGC to grade them.
Eventually I will slab my set but until then they are nestled in a Capitol holder and have ALL been treated with Blue Ribbon. Did it a few years ago and they still look just fine.

I might mention that I paint for a living therefore I do have some experience with Acetone. Not too pleasant on your hands so I can't imagine that it's good for a coin over time. After all I can always wash my hands and put some hand lotion on. Would you do THAT to your coins?

clembo

 

Ketone groups are relitively inert? Not in Glucose (or acetone). Never the less, I agree with the rest of this.

Ruben

 

1. Acetone is a ketone.
2. "Relatively inert" means just that - relative to other, more active substances, particularly those with oxidizing potential or acid / base properties.
3. Coins have very little glucose.

 

As another chemical engineer, I agree!