Grain refuse (4)
I believe the answer is:
bran
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">grain refuse</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 bran that I've seen before include "Type of edible fibre" , "Milled grain husks" , "Dietary fibre source" , "Husks valued as fibre" , "Refuse from grain" .)