Acetone: OK For All Kinds Of Coins? For How Long?

Looking good! Time well spent (mostly waiting) for the experience!

Acetone is chemically neutral to silver and gold, so it's not considered clearing (a soak, as you say scrubbing is different).

Acetone removes organic residue such as fingerprint oils, &c.

One word of warning, if the coin is spotted with organic material over time, removing it can show the fresh(er) metal from underneath the gunk, while the non-gunked areas show the results of general environmental exposure.

Acetone will not injure any coin.
Just do not use this solvent anywhere near a slab, or most album materials.

O.K ,thanks for the info , I will give the coin a bath and see what happens, only cost me $3. Cheers.

@TinyRetreat
I think it is personal choice. Some here, quite rightly would never clean a coin in any way, acetone, ultrasound, certainly not scrubbing, picking, wiping etc.
I think that most of those same people wouldn't collect very many coins that "needed a clean", concentrating mostly on slabbed coins or XF, AU and PF that were kept out of harms way, and away from circulation.
Speaking for myself, I like a good honest circulation coin sometimes more than a nice shiny boxed proof, and I haven't progressed to any slabbed stuff yet.
For the most part I don't touch them unless they are very grotty and green. When I feel that a coin needs to be 'restored', it involves soaking in 100% pure acetone, maybe a gentle pick with a distilled water-soaked bamboo skewer sharpened to a very fine point, perhaps the application of some Verdicare, and perhaps a soft wipe with a clean microfiber cloth.
This is not something I would do to a XF coin or higher, nor to a coin with a high value (and high is a subjective thing).
Here is an 1889 8 Doubles which I picked up for around $6 AUD. The build up of grease and green over time was enough to make me think it could do with a make-over.
For me it was worth the hour or so I spent carefully evacuating the grease and grime build-up from the recesses.
What BStrauss3 mentions is worth consideration. Any removal of organic muck will normally show the area underneath has a varied patina to the rest of the coin. Exposing the coin to the elements and some nice natural sunlight can help to mitigate the difference.

I'm only guessing but I'd think the fingerprint was fairly fresh, the acetone has removed all of the organic particles that it could, but maybe give it another soak, this time in a glass jar with a screw top lid to stop it evaporating. It can't hurt and may give a better result. It looks 100% better though, worth the effort for sure.