The Collaborative International Dictionary of English v.0.48:

Cleanse \Cleanse\ (kl[e^]nz), v. t. [imp. & p. p. Cleansed
   (kl[e^]nzd); p. pr. & vb. n. Cleansing.] [AS. cl[=ae]nsian,
   fr. cl[=ae]ne clean. See Clean.]
   To render clean; to free from fith, pollution, infection,
   guilt, etc.; to clean.
   [1913 Webster]

         If we walk in the light . . . the blood of Jesus Christ
         his son cleanseth us from all sin.       --1 John i. 7.
   [1913 Webster]

         Can'st thou not minister to a mind diseased,
         And with some sweet oblivious antidote
         Cleanse the suffed bosom of that perilous stuff
         Which weighs upon the heart?             --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cleanse
    v 1: clean one's body or parts thereof, as by washing; "clean up
         before you see your grandparents"; "clean your fingernails
         before dinner" [syn: cleanse, clean]
    2: purge of an ideology, bad thoughts, or sins; "Purgatory is
       supposed to cleanse you from your sins"

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "cleanse":
   beatify, bleach, bless, bowdlerize, canonize, clarify, clean,
   clean out, clean up, cleanse away, clear out, consecrate, dedicate,
   deliver, delouse, depurate, deterge, devote, discharge, disinfect,
   dry-clean, dust, dust off, enshrine, exalt, expiate, expurgate,
   free, free from, freshen, give release, give respite, glorify,
   hallow, intermit, lustrate, purge, purge away, purify, reform,
   release, remove, reprieve, saint, sanctify, sanitize, scavenge,
   scour, scrub, set apart, spruce, steam-clean, sterilize, suspend,
   sweep out, sweeten, tidy, wash, whiten, wipe, wipe off, wipe out,
   wipe up