Instrument some collected on the way back (5)
I believe the answer is:
cello
'instrument' is the definition.
(I know that cello is a type of bowed stringed instrument)
'some collected on the way back' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'on the way back' says the letters should be written in reverse.
'ollec' is hidden within 'collected'.
'ollec' backwards is 'CELLO'.
(Other definitions for cello that I've seen before include "big fiddle?" , "Music-maker" , "Lloyd Webber's instrument" , "Played by Rostropovich" , "music produced by this?" .)