wash (one's) dirty linen in public
To discuss very private, personal matters, especially that which may be embarrassing, in public or with other people. It always makes me uncomfortable when John starts going into all his personal problems whenever our friends get together. I just wish he wouldn't wash his dirty linen in public like that. People have an unnatural fixation on the personal lives of celebrities, but I don't see why they should be expected to wash their dirty linen in public.
give (one's) head for the washing
To submit passively to a reprimand, punishment, or some sort of mistreatment. I knew I was getting home after curfew, and that my parents would be angry about it, so I just gave my head for the washing and didn't try to sneak in. Don't just give your head for the washing—tell him that he can't talk to you like that!
wash a brick
To do or attempt something futile. That couch will never fit up the steps—tell them to stop trying to wash a brick!
wash (one's) hands
To clean one's hands, typically with soap and water. Kids, be sure to wash your hands before coming to the dinner table! Everyone in my class is sick, so I've been washing my hands constantly.