The Collaborative International Dictionary of English v.0.48:

Scummer \Scum"mer\, v. i.
   To scumber. [Obs.] --Holland.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Scummer \Scum"mer\, n.
   Excrement; scumber. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Scummer \Scum"mer\, n. [Cf. OF. escumoire, F. ['e]cumoire. See
   Scum, and cf. Skimmer.]
   An instrument for taking off scum; a skimmer.
   [1913 Webster]