I was training a new employee on the big machine today. Once, way back, she told me, she worked with a similar machine when she worked for the post office. She told me an anecdote about it during one of the rare moments when I wasn't talking a mile a minute in a desperate attempt to convey every thing I feel is important about running our big check in machine. I decided her anecdote would work best nipped, tucked, and only slightly mutilated into an allegedly comic story, or, stretching it, a joke.
One day, a large mass mailing promotion came through the mail machine. The promoter was sending out small packets of strawberry preserves in order to promote, well, his strawberry jam. I like to think it was a futile effort because the preserves were slightly rotten. I feel this will make the punchline funnier. Either way, the packets, in the letters, going through the machine's sorting rollers, would burst open, coating the innards of the machine miserably in sticky, sugary, rotten preserves, completely shutting the machine down.
It was a horrible jam.