The Collaborative International Dictionary of English v.0.48:

Soot \Soot\, v. t. [imp. & p. p. Sooted; p. pr. & vb. n.
   Sooting.]
   To cover or dress with soot; to smut with, or as with, soot;
   as, to soot land. --Mortimer.
   [1913 Webster] Soot