Could this DON bezel have been retouched a bit with a black permanent marker to make it look better ? Look at inner area between 11 and 12 o'clock
I'd actually say it's more likely just gunk / wrist slime, I've seen stuff like that left over on bezels after heavily polishing the crystal with polywatch too.
That is actually my watch and pic. dsio is correct, it was actually residue leftover from my watchmaker after he polished the crystal. I don't quite understand what you are trying to do here.
One of the most solid members on our forum our @Barking mad And happy to help many newbies on all things SPEEDMASTER over the years.
You would clean this in 3.2 seconds with a cotton bud.( Q tip ) You would not notice this at normal size.