Souvenir found in barrel I collected (5)
I believe the answer is:
relic
'souvenir' is the definition.
(I know that souvenir can be written as relic)
'in barrel i collected' is the wordplay.
'in' indicates a hidden word.
'RELIC' can be found hidden inside 'barrel i collected'.
'found' is the link.
(Other definitions for relic that I've seen before include "Reminder of times past" , "Piece left over" , "Object that has survived from the past" , "Memorial of saint" , "Surviving artefact" .)