The play received 'mixed' reviews. = The play's reviews were 'mixed'. [=some critics liked the play, while other critics did not]
I accidentally 'mixed up' the two files. [=I put each of the files in the place where the other one should have gone]
He 'got mixed up in' a plan to destroy the government. [=he became involved in a plan to destroy the government]
(..) - Hey, Mom. - Hello, dear. I washed your sheets. - What's that? - Arthur's handkerchief. - You're doing his laundry? - It must have gotten mixed into my things. - That's gross. - It's just a hanky. I know, and hankies are gross. - First of all, the word is gross. Hanky. - It's just a word. (..)2003 TvShow: Six Feet Under Title: Making Love Work Season: 3 Episode 6