The Collaborative International Dictionary of English v.0.48:

Deterge \De*terge"\, v. t. [imp. & p. p. Deterged; p. pr. &
   vb. n. Deterging.] [L. detergere, detersum; de + tergere to
   rub or wipe off: cf. F. d['e]terger.]
   To cleanse; to purge away, as foul or offending matter from
   the body, or from an ulcer.
   [1913 Webster]