title: Doesn't clear sandox after Quit game in IOS6
body: <p>I  created a turn based game by using game center.
  When I quit the game , in sandbox it doesn't clear.
  All quit games are listed in sandbox.
  How can I clear the sandbox ?
   Thank you.</p>
  
  <p><img src="https://i.stack.imgur.com/Ihlrf.png" alt="enter image description here"></p>