Question About Acetone?

Revisiting this topic, I've another suggestion to offer that I neglected to previously mention.

Keep in mind that the acetone treatment is every bit as much a means of conserving a coin as it is a means of (good) cleaning - removal of foreign matter that will eventually harm the coin's surface. So, don't forget to treat the third surface, the edge, be it reeded, plain or whatever. Failure to do this will result in encapsulation of some foreign material when the coin is housed in a flip or album; thus, resulting in the likely spread of contaminants at some future date.

yes. keep in mind, tho, that if it removes something that is protecting the surface underneath (oil, for example), the exposed surface will be highly reactive copper, subject to tarnish.

Well, I'm late to the party, but I'll add a few notes from my own experiences.

First, the "purity test" mentioned above is a pretty good test. Put some on a very clean piece of glass and let it evaporate. The glass should be as clean after as it was when you started. If the "acetone" (or toluene or any other solvent for that matter) leaves a residue, it's not pure.

Generally anything from a welding supply place is going to be the purest stuff you can get. Standards for welding are extremely high for purity. For example, welding oxygen tanks are nearly an order of magnitude purer than medical oxygen. You can breath welding oxygen. But never weld with medical oxygen. But I'm wandering way off topic there.

Avoid the "nail polish remover" for cleaning purposes. It generally fails the purity test with some serious residue left behind.

As for distilled water rinse, I'm going to disagree with others. I would use a distilled water rinse before going to the acetone. That would wash away any loose surface dirt (which potentially could be abrasive).

The reason I wouldn't rinse with distilled water afterward is because water evaporates more slowly than acetone. While the coin (or other object being cleaned) is wet, it will attract airborne dirt and contaminants. Acetone evaporates much more quickly and minimizes the time window where that can happen.

On other objects that I need to clean to a very high degree of cleanliness, I have been known to rinse with acetone after a cleaning with water based cleaning products and a distilled water rinse. The acetone will wash away the wetness from the distilled water and leave the cleaned object cleaner and drier quicker.

That's my experience. YMMV.