UI element wont destroy

I am making a game and in the begining i instantiate the main menu and i want it so when they press the play button it will destroy. heres the code:

void Start(){

     menu = Instantiate (mainMenu,mainMenu.transform.position, Quaternion.identity)as GameObject;
     menu.transform.SetParent (GameObject.Find ("Canvas").transform,false);

 }

 public void mainMenuPlayClick(){
     scoreKeeper = GameObject.Find ("Score").GetComponent<ScoreKeeper> ();
     paused = false;
     Destroy (menu.gameObject);
     print ("CLICKED");
     scoreKeeper.nextWave ();
 }

everything in the method works except the destroy.. please help!