It's a fiber/hair on the coin, not embedded into the surface. I don't see the big deal. Although it doesn't look the best, if looking at it closely. I think that if it's kept away from rapid temperature swings and humidity then no moisture will form on or around that fiber.
I wouldn't be so concerned about the hair itself, but more-so worried about whatever substance is adhering the hair to the coin in a manner which it hasn't fallen off in multiple postal trips. If the old ANACS holder was part of the reason the buyer bought the coin, breaking it out to give a quick acetone bath would be detrimental. I came across the original thread on reddit late at night when nothing was really going on and thought it was hilarious (and still do - just glad the buyer ended up satisfied despite being out a few bucks). I bet it was an unexpected sneeze during the slabbing procedure.
I once saw a 1917 ms64 buffalo nickel in pcgs slab on heritage rare coin galleries that had what looked like a pubic hair imbedded in the obverse of theslab. wonder how the heck that got there? maybe that makes it worth more money!
"Does a hair stuck on a coin qualify for details grade?" does this imply that the hair should carry a details grade itself on the slab? To be grammatically correct here, you are talking about grading the hair itself.
To be fair, you could probably remove the hair or fiber with some compressed air. Probably not even that is required.
Technically, a beard hair is what buffnix called it (and I called it before, but apparently that is a dirty word?.. I dunno, never considered it a dirty word before.)... just sayin'.
It's just in the wrong holder. NGC/PCGS could put a Mercanti signature label on it stating that it's his beard hair and double the price. just kidding... They would actually triple the price.
"Burton Strauss III said: ↑ Raise your eyes @@buffnixx - more likely a beard hair. Some people " And neither did I. You are missing the parts that I moved out of sight to "purgatory", and that was the cause of Burton's comment...just sayin' Jim
I seens it... I still don't understand how referring to a beard or underarm or leg hair by the term which was removed (which, btw, is how I originally referred to it in OP) to be derogatory. ..I guess things were different in the 1950's.