This one was heard on the TLC t.v. show, “My 600 lb. Life”. In context, it is a congruent conflation of “clear the air” and “get it off my chest”, both meaning to discuss or otherwise confront a troubling situation. Certainly weighing 600 pounds could be a troubling situation. Of course, taken literally, one may want to try a steam shower or an inhaler for really nasty chest congestion. A big thank you to regular malaphor contributor Mike Kovacs!