Destroying Custom Planes

Hi. I just learned about CustomPlanes and am using them for sprites (so that I can properly and easily make billboards) but am now having trouble destroying them. I am using these planes as I said, for sprites which are my enemies. I have a bullet script on my bullets but it does not destroy these planes. Here is the script:

using UnityEngine;
using System.Collections;

public class BulletScript : MonoBehaviour 
{
	float lifespan = 3.0f;
	
	void Update () 
	{	
		lifespan -= Time.deltaTime;
		if (lifespan <= 0) 
		{
			Explode ();
		}
	}
	
	void OnCollisionEnter(Collision collision) 
	{	
		if (collision.gameObject.tag == "Enemy") 
		{
			Destroy (gameObject);		
		}
	}
	
	void Explode () 
	{	
		Destroy (gameObject);
	}
}

Any help would be greatly appreciated. Thanks!

The Wiki CreatePlane script produces the mesh, but unlike the built-in planes, it does not add a collider. Depending on the needs of your game, you need to add either a mesh collider or a box collider to the planes. Select the plane in the hierarchy and use either Component>Physics>Box Collider or Component>Physics>Mesh Collider.