The phrase "whipping a dead horse" means to attempt to revive a moot point or issue. "Whipping a pile of horse bones" means to keep making futile and pointless attempts to revive interest in something that no one has cared about for so long its rotted away into a skeleton of its former self.
AKA: The Simpsons

Seasons 1 through 6 were the best. By season 8, FOX and Matt Groening were whipping a dead horse. Which means for the last 10 seasons they have been whipping a pile of horse bones.
by weasel1969 August 14, 2008
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