Playing golf with clients is one way to 'mix business with pleasure'. [=to do something enjoyable that is related to your work]
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]
(..) so I'm wiping them down with undiluted red wine vinegar. I've never heard of that. Oh, sure. For tougher spots, I use a - mix of denatured alcohol and water. And for those really intractable stains, I mean, we're talking shower doors, I wipe on lacquer thinner with a towel. (..)2006 TvShow: Desperate Housewives Title: Listen to the Rain on the Roof Season: 3 Episode 1