Little note inside Bruce's can (5)
I believe the answer is:
tinny
'bruce's can' is the definition.
(Australian term for a beer can)
'little note inside' is the wordplay.
'little' becomes 'tiny' ('tiny' can be similar in meaning to 'little'**).
'note' becomes 'n' (abbreviation).
'inside' indicates putting letters inside.
'tiny' placed around 'n' is 'TINNY'.
(Other definitions for tinny that I've seen before include "insubstantial" , "With thin metallic sound" , "Metallic-sounding" , "Made of poor metal" , "Cheap" .)