Use a spade (3)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">use a spade</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 dig that I've seen before include "Sly remark; excavate" , "Really like" , "Understand" , "criticism" , "Use a spade" .)
(Other definitions for delve that I've seen before include "Reach down and search" , "Intensively research (into something)" , "Rummage deep (in)" , "Dig up - search" , "Hollow" .)