Fig. to work out all right. (Alludes to a clothing stain that can be removed by washing.) Don't worry about that problem. It'll all come out in the wash.This trouble will go away. It'll come out in the wash.
if something secret or unpleasant comes out in the wash, people discover the truth about it They don't want the police to investigate, because they're afraid of what might come out in the wash.
in. to be dealt with in the normal chain of events. (As if someone were counseling someone who had caused a clothing stain.) Whatever it is, it’ll come out in the wash. Don’t worry.