soil

get one's hands dirty and dirty one's hands; soil one's hands 

1. Fig. to get closely involved in a difficult task. You have to get your hands dirty if you expect to get the gutters cleaned out.

2. Fig. to become involved with something illegal; to do a shameful thing; to do something that is beneath one. The mayor would never get his hands dirty by giving away political favors. I will not dirty my hands by breaking the law.

See also: and, dirty, get, hand

soil one's diaper(s)

[for a baby] to excrete waste into its diaper. The baby soiled his diapers. I detect that someone has soiled his diaper.