Is All Acetone The Same?

No, it is not. You want 100% pure acetone, usually from a hardware store. If the ingredients does not stop after listing only acetone, do not use it for coins.

Agree with Jbuck (above).

Nail Polish remover is not recommended for coin use. It has water, bitterants, and fragrance as additives.

This should help...

http://goccf.com/t/191678

Also read the two topics that Sap linked in his reply.

As you can see by the label, commercial acetone-based nail polish remover contains a bunch of other stuff besides acetone. These things either (a) smell pretty, or otherwise mask the "chemical smell" of the acetone, or (b) are skin moisturizers, to help counter the ability of acetone to wash the skin oil straight out of your pores, leaving your hands feeling dry. Then there's (c) water, which simply dilutes the acetone, bulking up the solution and making each bottle cheaper to manufacture, thus increasing the profits of the manufacturer, and (d) colouring agents, which just make it look pretty.

The things that smell pretty (in this case, that would be the "fragrance" and benozphenone) aren't likely to cause a problem; they are designed to evaporate away along with the acetone, so won't stay behind on the coin for very long.

The moisturizers (panthenol, lanolin, tocopheryl acetate, and whatever "wheat protein" is supposed to be - gluten, I'm guessing) are more problematic; they're deliberately designed not to evaporate away, but stay behind on your hands once the acetone evaporates. They will stay behind on your coin too, forming a thin greasy layer that won't wash off in water. This is the most undesirable side-effect of using such a product on coins. You'd basically need to wash the coin in 100% acetone to get this layer of goo off.

The water does not affect the coin directly, but does indirectly, in the sense that it makes the acetone more dilute, and thus less effective at goo removal.. The MSDS for this product declares that the acetone concentration is "less than 75%". So yes, 100% pure acetone will be much more effective than this diluted stuff.

The colours are much like the moisturizers: they're not designed to evaporate. They may change colour or even become transparent if they dry out, but they'll still be there. And, since denatonium is a mandatory additive to acetone products in some USA jurisdictions, there's probably some denatonium in it too.

None of these minor components are directly and acutely harmful to a coin (there's nothing acidic, and nothing containing sulfur). However, it's just not good practice to deliberately put gunk onto the surface of your coin - especially given that the whole point of an acetone soak is to remove gunk, not to replace the old gunk with fresh gunk.

Finally, in relation to the coins appearing in the thread linked in the OP: corroded coins like these are not going to be helped by acetone, either this stuff or 100%. Acetone removes "organic goo" - things like ink, paint, varnish, lacquer, and the green goo that forms on coins when left in plastic coin album pages for too long. To clean a corroded coin, you'd need something much stronger - vinegar, ammonia, sodium hydroxide, or chemicals like that. The end result is going to be a "cleaned coin", but these coins aren't "collectable" to begin with.

You don't show us the reverse, so it's hard to say. Goof-off is a brand name for an (overpriced) product containing a combination of aceton and xylene, so it shouldn't have a detrimental effect on your coin.

I've never heard of "Goof Off", so I Googled it. The MSDS is here, if curious.

Turns out the primary ingredient (about 50%) is methyl acetate. Methyl acetate is a polar solvent, similar to acetone, slightly more expensive and not as soluble in water. Other ingredients are acetone, xylene (a non-polar solvent insoluble in water), "Stoddard solvent" (a petroleum fraction slightly heavier than gasoline), methanol, and a handful of trace components like ethylbenzene and cumene (which are perhaps present as contaminants from the raw chemical feedstock, rather than deliberate additives).

I'm not entirely sure why the complex mixture is required, perhaps to impart a broad spectrum of polarities to the mixture so that it can be effective against a broader spectrum of "goo". I also don't see anything there that's harmful to coins. One thing for sure, that stuff isn't going to be readily soluble in water, so cleanup and disposal is going to be more problematic. It's also more toxic and more carcinogenic than acetone, but less flammable. So, trade-off.