Main element in pewter (3)
I believe the answer is:
tin
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">main element in pewter</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tin that I've seen before include "Canister" , "Ready" , "Metal element" , "Element, symbol Sn" , "Metal in Argentina" .)