Liquid wood preservative (8)
I believe the answer is:
creosote
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">liquid wood preservative</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for creosote that I've seen before include "Wood treatment" , "Wood preserver made from coal tar" , "Oily liquid obtained from tar" , "'Dark oily liquid, preserves wood (8)'" , "Oily liquid preservative -- eco-store (anag)" .)