Returned plans for tinned meat (4)
I believe the answer is:
spam
'tinned meat' is the definition.
(tinned meat product)
'returned plans' is the wordplay.
'returned' says the letters should be written in reverse.
'plans' becomes 'maps' (I've seen this before).
'maps' backwards is 'SPAM'.
'for' acts as a link.
(Other definitions for spam that I've seen before include "Unwelcome approach" , "Unwanted communication" , "Uninvited email" , "Tinned meat made largely from pork" , "one doesn't want on computer" .)