Hearth residue
(Other definitions for soot that I've seen before include "Carbon black" , "Chimney deposit" , "Carbon deposit from burning" , "Something stuck down the chimney" , "Black chimney powder" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hearth residue</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for ashes that I've seen before include "''... to ..., dust to dust'' (burial service)" , "Cricketing trophy - remains" , "Remnants of a fire" , "` `..... to ....., dust to dust' ' (prayer)" , "sporting trophy" .)