From Longman Dictionary of Contemporary Englishdo somebody’s dirty workdo somebody’s dirty workUNPLEASANTDISHONESTto do an unpleasant or dishonest action for someone, so that they do not have to do it themselves I’m not talking to him; you do your own dirty work! → dirty
Examples from the Corpus
do somebody’s dirty work• Tell Fran I'm not going to do her dirty work for her.• Her unnecessary decision to do the dirtiest work in the place struck them as alarming. 