Polish, perfect (6)
I believe the answer is:
refine
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">polish</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that polish can be written as refine)</span><br/ ><br/ >'<span class="explanation-format__original">perfect</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for refine that I've seen before include "Get rid of impurities" , "Purify or improve" , "Remove impurities as from oil" , "Remove impurities from (eg, metals)" , "Remove impurities or make cultured" .)