Metal currency (4)
I believe the answer is:
coin
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">metal currency</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for coin that I've seen before include "Make up" , "Create (phrase); metal token" , "Penny, say?" , "Invent a word or phrase - for money?" , "stamp" .)