Remove a blockage (6)
I believe the answer is:
unplug
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">remove a blockage</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 unplug that I've seen before include "Disconnect (kettle or toaster?)" , "Remove power from" , "Disconnect (an electrical device)" , "Take out of socket" , "Remove from a socket" .)