Alloy containing tin (6)
I believe the answer is:
pewter
'alloy containing tin' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pewter that I've seen before include "Grey alloy of tin and lead, makes mugs etc." , "Beer-tankard alloy" , "Plate" , "Silver-grey alloy" , "Tin alloy used in tankards, etc" .)