Buff (6)
I believe the answer is:
polish
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">buff</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 polish that I've seen before include "Brush up" , "Buff - from Poland" , "Language (linked to spitting?)" , "make things shiny" , "Smooth or shine by rubbing" .)