I have some DEC Correspondent Ribbons in the same packaging. Had them since 1986.
Last year I took one out to use, and it was actually
better than new.
To explain - Back in the day, when ribbons were brand new, they were too "wet" and they expended their ink too quickly. Of course, this produced incredibly black print, [for a while] but it smudged easily and successive printouts were substantially less intense.
So, we quickly learned to open the bag for a new ribbon, and leave it near the printer for a month or so. This evaporated the ink enough to make it last better. In the end, this practice tripled the lifespan of a ribbon, and it gave more consistent quality output of during that life.
DEC Ribbons were better than other manufacturer's [I.E. - INMAC] but the same tendencies were there regardless. DEC Ribbons re-ink better too.
The aged ribbons I have now, don't need a full month of exposure once opened, and seem to last better anyway.
What printer are your ribbons for? I might be interested in a couple LA-120 Ribbons.
I don't use mine much... the price of a box plain tractor-feed 11x17 paper is
astronomical here. A ribbon or two might keep me for the rest of my life.
