Boy's brown tin (6)
I believe the answer is:
duncan
'boy's' is the definition.
'brown tin' is the wordplay.
'brown' becomes 'dun' (dun is a kind of brown).
'tin' becomes 'can' ('can' can be a synonym of 'tin').
'dun'+'can'='DUNCAN'
(Other definitions for duncan that I've seen before include "innovative dancer" , "King murdered by ambitious Macbeth" , "Scottish king" , "Man's name" , "Isadora ..., pioneer of modern dance" .)