A call to OnMouseExit follows the corresponding calls to OnMouseEnter and OnMouseOver.
This function is not called on objects that belong to Ignore Raycast layer.
This function is called on Colliders marked as Trigger if and only if Physics.queriesHitTriggers is true.
You can use OnMouseExit as a co-routine if you add a yield statement somewhere in the function. This event is sent to all scripts attached to the Collider or GUIElement.