WordNet (r) 3.0 (2006):

unclutter
    v 1: rid of obstructions; "Clear your desk" [syn: unclutter,
         clear] [ant: clutter, clutter up]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "unclutter":
   clarify, clear, clear up, disburden, disembarrass, disembroil,
   disencumber, disengage, disentangle, disintricate, disinvolve,
   extricate, free, free up, liberate, ravel, sort out, unbraid,
   uncoil, unknot, unmix, unravel, unscramble, unsnarl, untangle,
   unthread, untwine, untwist, unweave, unwind