Some dross in Italian composer (7)
I believe the answer is:
rossini
'composer' is the definition.
(I've seen this before)
'some dross in italian' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'ROSSINI' is hidden in the letters of 'dross in italian'.
(Other definitions for rossini that I've seen before include "opera producer" , "Composer born 29 Feb 1792" , "Largo al factotum composer" , "he scored regularly" , "he produced harmony" .)