Any old thing literally! (6)
I believe the answer is:
cliche
But I can't explain it at all! Could you help me understand?
(Other definitions for cliche that I've seen before include "Well-worn phrase" , "Hackneyed expression" , "Stereotyped expression" , "Tired 21/12 [TURN OF PHRASE]" , "Saying made tedious through over-use" .)