It takes a genuinely dull blade not to find allegory in an action scene involving kids taking a dip into a murky lake teeming with merfolk and the drowned bodies of friends. (filmfreakcentral.net)
You may need to clean the blender after pureeing the steak - sometimes bits of gristle will dull the blades making chopping up the shrimp difficult! (sbnation.com)
A heavy stress on complexity, realism and limitations has a way of dulling the blade of social change. (religion-online.org)