just before I just covered it for the night I took another photo, doesn't look like much has changed in this photo.
I looked at the coin before I left for work this morning and it looked unchanged, will pull it out when I get home tonight.
Since it seems to be working, before ya remove it, make sure ya swish it around well to remove any loose or dissolved material. From there I would recommend following the full methodology I have listed in this thread - https://www.cointalk.com/threads/proper-acetone-procedure.193708/
It looks better. Perhaps remove and rinse with distilled water, (air or lightly pat dry) and put it in a new container with some fresh xylene. I was against the next step as I think ammonia might be a mistake.
I was just thinking the current xylene could be contaminated with whatever this "super milk spot" is, and I would toss that mixture and use fresh.
"Tossing" xylene is a bit tricky. It doesn't mix with water (so "rinsing with distilled water" doesn't work so well). Burning it off (outdoors!) might be best, although I seem to remember it makes a really sooty flame.
I was thinking if you just leave it in an open container it would evaporate. But I am not familiar with xylene.
after 23 hours I do not feel there is much difference. Dumped out old, rinsed with distilled water and put it back into fresh xylene dip for another 24 hours.
It's a nice coin as you can see by the reverse. Perhaps the photo in the xylene looked better than it actually was. If it won't hurt the coin, I'd leave it in there for a day or even 2 or more if it is safe to do so. It would help to know what the contaminant is. Because then there would be a way to fight it, neutralize it, etc.
"That's why I am also surprised that others have not seen this before". I have never seen such phenomena either. I know the Pilofilm is porous, but such a reaction must have been perpetrated from another source instead of the storage conveyance. If anything, the coin would have colorfully toned in such storage situations. Good advertisement for Burma Shave, though.....
Now I'm not sure how it would work on coins, or if it may even damage it, but how about methyl ethyl ketone? I use it working with aluminum parts in the Aerospace industry oh, and it is one tough solution.
Only post a photo of the reverse and offer it for sale as a grab bag coin. The goo does look thinner than originally, so something happened. When you compare photo #109 with the OP.
Boy, whatever it is on that coin it sure looks thinner and fainter than it did in the original pic you posted - Some small spots/sections of it appear to be gone altogether. So I kinda gotta believe that the xylene is at least having some effect on it. Not that I really believe it will all ever come off, it's just interesting because I've never seen anything even remotely like it. Now I gotta admit, I thought the same kinda thing the 1st time I met Ken in person, but ........... 1,369 You better watch out, I'm catchin up Ken
I wouldn't expect MEK to be much different from acetone. It doesn't evaporate quite as quickly, and it's got a higher boiling point, so I guess you could use it at higher temperatures, which would make a difference. At room temp, though, I suspect they'll behave about the same.