To do someone else’s dirty work. This term comes from an ancient fable in which a monkey, not wishing to burn its own fingers, persuades a cat to retrieve chestnuts that had fallen into the fire (whence also cat’s paw, for being made a dupe). Recounted in numerous early collections of fables (by La Fontaine, 1678, and Sir Roger L’Estrange, 1692, among others), it was transferred to any kind of dirty work by the eighteenth century.