MonoBehaviour.OnTriggerExit

function OnTriggerExit (other : Collider) : void

Description

OnTriggerExit is called when the Collider other has stopped touching the trigger.

This message is sent to the trigger and the collider that touches the trigger. Note that trigger events are only sent if one of the colliders also has a rigid body attached.

JavaScript
// Destroy everything that leaves the trigger

function OnTriggerExit (other : Collider) {
Destroy(other.gameObject);
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void OnTriggerExit(Collider other) {
Destroy(other.gameObject);
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def OnTriggerExit(other as Collider):
Destroy(other.gameObject)

OnTriggerExit can be a co-routine, simply use the yield statement in the function.