Soft, soft metal to make a case (5)
I believe the answer is:
plead
'make a case' is the definition.
(I've seen this in another clue)
'soft soft metal' is the wordplay.
'soft' becomes 'p' (musical abbreviation for 'piano').
'soft metal' becomes 'lead' (I've seen this before).
'p'+'lead'='PLEAD'
'to' is the link.
(Other definitions for plead that I've seen before include "Argue (a position in court)" , "Argue (for a cause)" , "Request" , "Supplicate" , "Say one is guilty or not guilty" .)