The Collaborative International Dictionary of English v.0.48:

Coom \Coom\, n. [Cf. G. kahm mold gathered on liquids, D. kam,
   Sw. kimr["o]k pine soot, smoke black, Icel. k[=a]m grime,
   film of dirt.]
   Soot; coal dust; refuse matter, as the dirty grease which
   comes from axle boxes, or the refuse at the mouth of an oven.
   --Phillips. Bailey.
   [1913 Webster]