Silvery-white metal (9)
This clue is a double definition.
'silvery' is the first definition.
(thesaurus)
'white metal' is the second definition.
(I've seen this in another clue)
(Other definitions for tin that I've seen before include "A silvery-white metal often in cans" , "Cornish metal?" , "Metal element" , "Silvery white metal" , "loaf of bread" .)
(Other definitions for nickel that I've seen before include "not worth much in America" , "Metallic element; US coin" , "Metal - 5 cents" , "US five cent piece" , "5c coin" .)
(Other definitions for magnesium that I've seen before include "Silver-white metal" , "flammable element" , "member of a second group" , "Metal element, Mg" , "Silvery-white metallic element" .)