Cutting tool used to be returned (3)
I believe the answer is:
saw
'cutting tool' is the definition.
(I've seen this before)
'used to be returned' is the wordplay.
'used to be' becomes 'was' (I've seen this before).
'returned' says the letters should be written in reverse.
'was' reversed gives 'SAW'.
(Other definitions for saw that I've seen before include "Old saying with teeth" , "Implement for cutting wood" , "Wood-cutting tool" , "Caught sight of" , "Noticed; cutter" .)