Small box (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">small box</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 casket that I've seen before include "Jewel box" , "Small box to hold jewels" , "Small box or chest" , "Helping boost" , "Small box - coffin" .)
(Other definitions for carton that I've seen before include "Cantor (anag)" , "He did a far, far better thing" , "fictional lawyer" , "Light cardboard box" , "Small, light box or container" .)