Will soaking a proof coin in acetone put spots on the finish?

I decided to pull out a proof coin and do a test with photos after being called out by idhair saying acetone will not damage a proof coin.

I say acetone will damage a proof coin mirror finish by leaving white spots similar to milk spots.

What say you all?

I'll post my photo results after a few days as to not skew the initial results.

 

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No, I don't think it will have any effect.

 

I saw your other post. No I don't think it hurt the coin. The acetone doesn't leave the spots. All the acetone does is remove any organic material from the coin. The spots that remain are non organic substances or thicker spots of organic material. The spots were always there, just the acetone dip brought them out more.

This is why Ezest or MS-70 are more recommended for modern proof coins. Some people do both. Acetone 1st then one of the other 2.

 

I have used acetone on a lot of Proof Franlkins before sending to NGC for grading.
No problems on any of them.

 

NO, But if someone put some material ( on the proof to produce a 'shine' , mirror) such as some of the old saturated hydrocarbon treatments, perhaps oils or waxes. the acetone can react with those and produce residue if not used properly. Pure acetone can not chemically react with the metal in a livable environment. Would be like putting only distilled water in your Brigg's mower gas engine and expect it would run it.

 

No.

 

I've never tried it, nor have I seen results from someone else trying it. I'm going to have to go with "not sure" until you post your results!

 

Acetone only melts organic stuff that's on the coin. What's under that organic stuff may not be pretty. The acetone is dirty after the first bath. A second or third bath in fresh acetone help wash that away.
Take a drop of the acetone from the first bath and let it dry on a piece of glass. That will give you an idea of what is floating around in the solution. Do that with each batch and you know when you have washed away everything the acetone can help with. I have never harmed a proof with acetone.

 

Chemistry says NO. See post 3 and 5

 

IMO, no BUT, if the acetone is dirty, it will leave a haze.
BUT, that haze can be removed with clean acetone.

I had a 2009 Lincoln DDR Proof tht had some haze and dipped it in dirty acetone. The haze got worse.

I then dipped it in fresh, unused acetone and it came off.

But thats just my opinion since I normally only use acetone on gunked up coins.

 

Sure, my understanding of chemistry and how it has been explained related to coins says no, but I haven't seen it firsthand and so I'm not going to try to stake a claim I cannot 100% verify. I would hate to use second/third hand information and give someone bad advice. I am interested in the outcome of this experiment.

 

No. Acetone will NOT damage a proof coin... any spots you are observing are deposits either from using non-pure acetone (lab grade is necessary) or contamination affected by the acetone. Acetone will not react with metal. I have done extensive experimentation with acetone, besides my chemistry background.

 

I need to ask why anyone would think that "soaking" a proof in acetone is necessary?

I have dipped a Copper Proof to remove haze but never felt the need for a "soak" since, if it doesn't clean up with a quick dip, no amount of "soaking" is going to clean it up. (Proof coins)

"Soaking", IMO, is for the removal of large quantities of organic junk and typically on circulated coins.

Modern Proof coins that have a need for "conserving" dip quite nicely in E-Z-Est but it has to be a very quick dip (less than a second) otherwise the copper core will turn pink.

 

I have seen some coins NOT be affected and others leave spots or blemishes. Regardless, you should not use acetone or ANY chemical on coins as it does deteriorate the finish and...is noticable that the coin has been cleaned which lowers the value.

This being the case, if you wish to "undirty" a coin for your own collection and do not plan to sell ever, you can use toothpaste (which will remove surface dirt) on a soft cloth without harming the coin or finish and then a light soap to complete the process. This is performed by many coin dealers and is very safe.

 

Wait, you've just publicly denied the widely-known scientific certainty that acetone cannot alter the metal of a coin, and then advocated using an abrasive to "clean" up coins?

I use toothpaste to polish the scratches off of slabs....

 

Is there a "worst answer" option?

Acetone does not "deteriorate the finish".

Rubbing with toothpaste will absolutely leave hairlines on the metal of a coin.

 

Unbelievable.... once again...Acetone does not "deteriorate the finish". - is totally WRONG!!!!! Acetone will not affect metal. Rubbing toothpaste - an abrasive - WILL ruin the surface of a coin.....

 

Not second or third hand information. It's basic chemistry.

Acetone is a solvent because its molecule has a charged end. The energy in the charged end can react and break bonds of other molecules with weaker bonds. A lot of organics have weaker bonds and love to give up atoms/molecules to acetone. This breaks down the organic molecule and allows to be easily dissolved and/or removed. Metals and toning compounds such as AgS are held together with much stronger bonds. There just isn’t enough energy in solvents like acetone or water to break metallic bonds.

Dips work differently. They cause a chemical reaction to occur with the toning compounds. This chemical reaction breaks the stronger bonds and removes the toned layer. Since the toned layer contains atoms from the original surface, actual metal from the coin is removed

The following was written with apologies to all the chemists out there who are probably cringing after reading this simplistic explanation (I should have listened to Dr. Bentz and taken organic chem like he recommended ). Please jump in and correct any errors or inconsistencies.

 

Not to use a proof. But, as an experiment, a copper coin, a nickel, a clad coin, and a silver coin, should be put in four separate sealed glass jars with 100% acetone. And left for a year.
Then next year post the results. (Before and after pictures).

 

For extra fun, make it six jars, and quartz (that transmits ultraviolet), not glass.

Put all six in a climate-controlled room. Put a strong UV light on three of them; keep the other three in the dark, but at the same temperature.

No, wait. The "acetone may attack copper eventually in some cases" claim also mentions moisture. So, twelve jars, six of them containing damp acetone...