title: How to effectively handle removal of objects with Corona SDK?
body: <p>I have a button that creates and apply force every time the the button is touched.
  How do I prevent this from leaking memory?</p>
  
  <p>I am using director class to change from scene to scene.
  Here is the code:</p>
  
  <pre><code>-- Fire the rocket from the jet position
  local function fireTheRocket(event)
      if event.phase == "ended" then
        local fireBall = display.newImage( "rocket.png")
        fireBall.x = jet.x; 
        fireBall.y = jet.y; 
  
        GUI:insert(fireBall);
  
        physics.addBody(fireBall, "dynamic")
        fireBall:applyForce( 1000, 0, fireBall.x, fireBall.y )
      end
  end
  fireBtn:addEventListener("touch", fireTheRocket)
  </code></pre>