How To Tell If An "Old Cleaning" Has Been Done?

Lots of hairlines, absence of luster, all covered and smothered by a new skin of toning. That's just one way to discern old cleaning.

Good golly, all you have to do to remove wax is an acetone soak, and nobody would ever know you did it. Unless that was what he was referring to as "cleaning," it'd cost me a bunch of confidence in that dealer.

I may have misspoken, SsuperDdave. That is exactly what he said he did: give it an acetone soak. I was paraphrasing (perhaps too generally) when I said he cleaned it. I have a lot of confidence in this dealer, especially since he volunteered this information when I was examining the coin.

So, is an acetone soak a process that most collectors here would not find too offensive? Also, my apologies to arkmanxx, I may have changed the subject in this thread.

SsuperDdave, I think that is an excellent distinction to make that I hadn't really considered: cleaning vs. conservation. Can you please elaborate a bit on what you mean by "the right coin". Are you referring to the type of metal (copper vs. nickel vs. silver) or a coin that is heavily soiled vs. one that is only slightly dirty.
Thanks!

You have to be first, cognizant of what (I'll use acetone, but other "acceptable" procedures qualify for the same interpretation) acetone can and can't do. Acetone is an organic solvent, and will only affect organic substances on a coin. It cares not at all for toning/tarnish, which isn't organic, and won't affect it. You got PVC byproduct contamination? Acetone is imperative. Tape residue? Probably, depending on your personal opinion of the result.

Second, you need to understand what is and isn't an appropriate candidate from an appearance standpoint. Never forget that the goal is to leave a coin in its' original state - exactly as its' lifetime of use or non-use by innocent people has left it - accept the life as it has lived and be happy with the result. Circulated coins accrue crud, sometimes. Acetone can remove that crud, sometimes. The coin will be darker where the crud is, and a bit lighter where the crud isn't, but those dark and light spots will be there for two different reasons. One is outside stuff choosing to cling to the coin; the other is normal environmental/chemical processes. We call it "toning" or "tarnishing," depending on how "pretty" we think it is. Same process, same result, choose your own adjective.

If what you do ever makes that coin look unnatural, you have failed. The only exception is PVC contamination, which could eventually dissolve the whole darn thing and is the enemy of us all. It is your duty as a numismatist to stop it whenever you find it, to preserve your temporary possession for those who follow. But that "dark/less dark" coin which could be changed by acetone is going to be adversely affected by the process. It will change from "dark/less dark" to "less dark/light" because the crud-covered part hasn't toned, what you've removed will reveal surfaces more original, and anyone with half a clue will know the coin has been treated. That is....sub-optimal.

So sometimes you have to live with a cruddy coin, as the lesser of two evils.

Agreed!

Some people are are not addressing the question very well with the acetone off-shoot discussion. I think the OP wants to know how he can spot an old cleaning when he's looking at coins to potentially buy.

Coins that had an "old cleaning" were usually 19th century or early 20th century silver types. Copper was cleaned as well, but is usually much more obvious to spot. No nickel type has ever been cleaned with much frequency. These old cleanings were usually done on coins that would grade about XF and AU as these were the nice looking keepsakes that these early collectors wanted. The MS coins, usually, though not always, were left alone as they already looked good enough. People back then didn't bother to clean lower graded coins as much. Many of these lower graded cleaned coins, which are rampant, were actually done in the modern era (since the 60's possibly) by stupid and/or unethical sellers. These have not had the time to really re-tone and are thus, also easy to spot. The primary thing people wanted to achieve when doing their cleaning was to remove grime and increase shine. An expert eye can generally spot an old cleaning just by a glance at color versus many they've seen before. Most of these re-toned old silver coins were never re-circulated so they never got any new grime. So to finally answer your question, one good way to spot an old cleaning is to look for a coin that shows wear and has a surprisingly even tone, yet no grime, even in well-protected crevices.