Whitesmiths work with it (3)
I believe the answer is:
tin
'whitesmiths work with it' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tin that I've seen before include "With copper, makes bronze" , "Element, symbol Sn" , "Metal in Argentina" , "Cornish metal?" , "loaf of bread" .)