Sample small potato bags (6)
I believe the answer is:
taster
'sample' is the definition.
(I've seen this before)
'small potato bags' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'potato' becomes 'tater' (synonyms).
'bags' indicates putting letters inside (bag can mean secures or steals).
's' placed inside 'tater' is 'TASTER'.
(Other definitions for taster that I've seen before include "Food tester" , "Brief sample" , "A sample to try" , "person in charge of testing" , "extract" .)