The Collaborative International Dictionary of English v.0.48:

Sponge \Sponge\, v. t. [imp. & p. p. Sponged (sp[u^]njd); p.
   pr. & vb. n. Sponging (sp[u^]n"j[i^]ng).]
   1. To cleanse or wipe with a sponge; as, to sponge a slate or
      a cannon; to wet with a sponge; as, to sponge cloth.
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   2. To wipe out with a sponge, as letters or writing; to
      efface; to destroy all trace of. --Hooker.
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   3. Fig.: To deprive of something by imposition. "How came
      such multitudes of our nation . . . to be sponged of their
      plate and their money?" --South.
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   4. Fig.: To get by imposition or mean arts without cost; as,
      to sponge a breakfast. --Swift.
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