Bumping an old thread, to add items to it, from my own postal history collection. Just as you did, Glenn, I was looking through boxes of stuff I had saved from years ago, and found these two solo-use, Year of the Pig, USA covers.
The next day, January 1, 1995, the 1st ounce postage rate in the US increased from 29c to 32c so this stamp could only be used as a solo use for 2 days.
I think these stamps were distributed nationwide to U.S. post offices and to no surprise, some were sold a little early. I have a 30 Dec 1994 cancel from Cedar Rapids, Iowa and a 29 Dec 1994 cancel from Des Moines, Iowa. I am still looking for a 31 Dec 1994 cancel in my stuff, as I have not found one of those yet. Does anyone know the "Earliest Known Use" that has been found of this stamp?
By the way, these were also saved out of the trash can at work, as were a lot of the covers I show on this forum.