Large Cents In General

if they have a bunch of dirt on them, clean with nail polish remover (acetone), rinse with distilled water, and pat dry with a clean cotton cloth or swab. dont brush them. store them in a cool and dry place.

any inactive ingredients dissolved in nail polish remover will also dissolve in water, therefore rinsing the coin afterward will remove unwanted compounds on the coin's surface. the ingredients in the nail polish remover will not damage the coin unless combined with a reactive chemical or enough heat is used to decompose them and oxidize the metal, so do not light coin on fire, simple. I forgot to mention, distilled water is important. trace compounds in tap water can cause the copper to react with the oxygen in the air over time. all copper coins will oxidize evdentually unless you keep them in a sealed vacuum or an inert gas like argon. heat, moisture, and a variety of compounds speed up the process so storing in a cool dry place will protect the coins from damage.
better?

I have heard that nail polish remover shouldn't be used (never tried - just was told) because other chemicals in the remover can damage coins. I was told only 100% acetone should be used.

Yes. if you use acetone, you would buy the straight stuff from the paint section of the hardware store.

I wasn't planning on cleaning my coins. But when I heard what I did on the tape, I wanted to ask. I seem to recall reading *somewhere* that acetone discolors copper(?)

Acetone will not "clean" a coin in the sense that it is normally thought about. Cleaning is generally thought of as being a bad thing and damaging to coins. Acetone is an organic solvent that will only remove organic material and will not alter or react with the metal surface.

Acetone itself will not discolor copper but an old method of protecting copper coins was to apply lacquer to them. Acetone will remove the lacquer but the lacquer itself may have already reacted with the copper causing a discoloration that is only revealed once removed.

What's the date on the VHS tape? There have been different views on how to care for coins over the years. At one time brushing, wiping with a cloth, or even polishing coins was acceptable. I guess there are some things that can, or even should be done if the coin is heavily corroded, but I don't clean mine.

Brushing with a fine camel hair brush was considered the norm for caring for copper years ago and I imagine some old timers still do it today.

http://www.pcgs.com/articles/article2341.chtml

If green corrosion appears on the surface of a copper coin, remove it mechanically, if possible, usually with a soft camel-hair brush. Copper aficionados sometimes have brushes they have used for decades, carefully protecting them. These "used" brushes have oils from years of use and their owners swear that these "protect" the surfaces of copper coins brushed by them. There is truth to this, as many coins brushed appear unchanged after many years. These, however, should only be used by knowledgeable copper experts, because even the fine camel hair can damage surfaces. Only when this method has been tried and failed should one attempt to remove something chemically from the surface of a copper coin.

quote:

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any inactive ingredients dissolved in nail polish remover will also dissolve in water, therefore rinsing the coin afterward will remove unwanted compounds on the coin's surface. the ingredients in the nail polish remover will not damage the coin unless combined with a reactive chemical or enough heat is used to decompose them and oxidize the metal

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Not true at all. What dissolves in acetone will not necessarily dissolve in water and vise versa. Back to Chemistry 101

There are two kinds of solvents- polar and non-polar. I won't get into the specific differences because it involves terms such as "dipole moment" and "dielectric constant" and the chemistry explanation of that would be incredibly confusing to non-scientists not to mention very lengthy so I will go with the simple explanation.

Water is a highly polar solvent and will readily dissolve polar compounds like inorganic salts. Non-polar solvents such as hexane or benzene will dissolve other non-polar compounds, mainly hydrocarbons. Acetone is a weakly polar solvent meaning that it is miscible(able to mix) with water but it cannot dissolve compounds that are strongly polar. As an example, try dissolving table salt(sodium chloride) in acetone- you won't be able to do it. Since acetone is only weakly polar, it is a decent solvent to dissolve some weakly non polar compounds. It won't work with all hydrocarbons but it will work on many substances that can be found on coins and it is relatively harmless compared to other organic solvents. Water will not dissolve hydrocarbon compounds that acetone can dissolve. The old adage "oil and water don't mix" is a key phrase that comes to mind and applies here.

Nail polish removers do not provide a full list of ingredients due to trade secrets and the like. Usually general descriptions are the norm, i.e. dyes, fragrances, etc.- they just don't tell you exactly what they are though. Many of those compounds could be weakly polar or non polar and they would not be miscible with water so a water rinse would do nothing to remove them.
Another fly in the ointment so to speak is the fact that many nail polish removers do not even contain acetone anymore- the main ingredient is MEK(methyl ethyl ketone aka butanone).

As a trained chemist, I absolutely hate to see misinformation and bad advice such as this. Do not take my post as a slam because it is not, it is strictly educational. Just be aware that you should not be applying substances to a coin if you have no comprehension of the chemistry behind it.

biokem,
i did not know there were exceptions where a polar solvent can dissolve a nonpolar substance.
so... acetone will dissolve some weakly non-polar chemicals because its polarity is not enough to repel a nonpolar, but a highly polar chemical like water will not dissolve nearly any nonpolar? is that right?