Exchanges damaged red tins around mid-May (6,2)
I believe the answer is:
'exchanges' is the definition.
(trading in is a kind of exchanging)
'damaged red tins around mid-may' is the wordplay.
'damaged' indicates anagramming the letters.
'around' is an insertion indicator.
'mid' indicates the central letters.
The middle letter of 'may' is 'a'.
'redtins' is an anagram of 'trdesin'.
'trdesin' enclosing 'a' is 'TRADES IN'.
(Other definitions for trades in that I've seen before include "exchanges" , "Hands over an object as part payment for a new one" , "'Hands over the old object in part payment for the new (6,2)'" .)