Make tidy (6)
I believe the answer is:
neaten
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">make tidy</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 neaten that I've seen before include "Trim" , "Groom" , "set in order" , "Straighten up" , "Make tidy" .)