Yeah, the Post Office is really down on shipping anything in a jar. I understand that, things break, packages leak, and that is not good for other people's mail. And all because someone ain't got the good sense God gave a goose to pack the jar/bottle such that rough handling won't break it.
As some folks here may attest, I have shipped glass jars of honey. I usually wrap the jar in several layers of plastic bag. Then the jar is slid into a box that has room on all four sides. I then prop the jar with wedges of styrofoam so that it is away from the cardboard on all sides, and I seal up the box. Last step, I poke a hole in the side of the box, stuff in a nozzle from a can of Great Stuff Foam Insulation and pull the trigger!!! Harder than heck to get the honey out when it arrives, but so far none of the jars have broken either!!!