Problem with Touch Dispatcher when changing scenes?

I am having a Menu_Items class which extends CCSprite and CCTouchDelegate.
In one scene I added that Menu_Items sprite to a layer. On clicking it I change the scene.
But on my new scene it is still detecting touch for that old sprite and the scene is reloading, though the sprite is not visible.
I tried removing touchdelegate from sprite when I click it once, but its not working?
What could be the problem???