[1] : WordNet (r) 2.0

clean slate
     n : an opportunity to start over without prejudice syn: fresh
         start, tabula rasa
see also:
fresh start tabula rasa 

[2] : Moby Thesaurus II by Grady Ward, 1.0

59 moby thesaurus words for "clean slate":
   blamelessness, blank, bloodless revolution, bouleversement,
   breakdown, breakup, cataclysm, catastrophe, clean sweep,
   cleanliness, cleanness, clear conscience, computer revolution,
   convulsion, counterrevolution, debacle, empty space, faultlessness,
   guiltlessness, immaculacy, impeccability, inanity, innocence,
   innocency, innocentness, nothing, nothing to hide, nothingness,
   offenselessness, overthrow, overturn, palace revolution,
   prelapsarian state, purity, radical change, reproachlessness,
   revolt, revolution, revolutionary war, revulsion, sinlessness,
   spasm, spotlessness, stainlessness, striking alteration,
   subversion, sweeping change, tabula rasa, taintlessness,
   technological revolution, total change, transilience,
   unblemishedness, unguiltiness, upset, vacuum, violent change, void,
   whiteness

Clean Slate >> C Words
Clean Slate, definition of term: Clean Slate
clean+slate_pag1.html

Slate >> S Words
Slate, definition of term: Slate
slate_pag1.html

Clean >> C Words
Clean, definition of term: Clean
clean_pag1.html

Clean Out >> C Words
Clean Out, definition of term: Clean Out
clean+out_pag1.html

Clean Up >> C Words
Clean Up, definition of term: Clean Up
clean+up_pag1.html