WordNet (r) 3.0 (2006):

clean up
    v 1: put (things or places) in order; "Tidy up your room!" [syn:
         tidy, tidy up, clean up, neaten, straighten,
         straighten out, square away]
    2: make a big profit; often in a short period of time; "The
       investor really cleaned up when the stock market went up"
    3: dispose of; "settle the bills"
    4: make oneself clean, presentable or neat; "Clean up before you
       go to the party"

Moby Thesaurus II by Grady Ward, 1.0:

89 Moby Thesaurus words for "clean up":
   bleach, bowdlerize, button up, cap, capitalize on,
   carry to completion, cash in on, clean, clean out, cleanse, clear,
   clear out, clear the decks, clear up, climax, close out, close up,
   coin money, commercialize, complete, conclude, crown, culminate,
   delouse, depurate, deterge, dry-clean, dust, dust off, end,
   expurgate, finalize, finish, finish off, finish up, fix up,
   freshen, gain, gain by, get done, get it over, get through,
   get through with, groom, gross, lustrate, make, make a killing,
   make money, make money by, mop up, neaten, net, perfect, police,
   police up, profit, purge, purify, put in trim, realize, realize on,
   reform, round out, scavenge, spruce, spruce up, steam-clean,
   straighten up, sweep out, sweeten, terminate, tidy, tidy up,
   top off, top out, trig up, trim, trim up, turn a penny,
   turn to account, turn to profit, whiten, wind up, wipe, wipe off,
   wipe out, wipe up, wrap up