I'm noticing that when a user logs out, all of the previous view controller objects are still stored in memory

current code in the logout page:

```
 @IBAction func LogOutClicked(sender: AnyObject)
{
    let appDomain = NSBundle.mainBundle().bundleIdentifier
    NSUserDefaults.standardUserDefaults().removePersistentDomainForName(appDomain!)
    self.performSegueWithIdentifier("goto_loginpage", sender: self)

}

```

current code on home page:

```
override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated);

    MyVariables.prefs = NSUserDefaults.standardUserDefaults()
    let isLoggedIn:Int = MyVariables.prefs.integerForKey("ISLOGGEDIN") as Int

    //not logged in
    if (isLoggedIn != 1)
    {
        self.performSegueWithIdentifier("goto_login", sender: self)
    }
        //logged in
    else
    {
      // Start Filling objects with data
    }
}

```

The Logout button is on a separate view controller than the view controllers I'm trying to clear from memory and remove all the objects from