Waste matter (5)
I believe the answer is:
dross
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">waste matter</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that dross is a type of waste matter)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for dross that I've seen before include "Scum - dregs" , "Waste coal - rubbish" , "Something of inferior quality" , "Lees" , "Rubbish, scum" .)