on collision destroy original and keep instantiate

hi,
i have viewed this unity api part 1 17 instantiate on Vimeo
but i dont want the original particles to play, i need only the on collision the particles should come out , dont want the extra particles on side in the scene… how to do this. i am a newbie, please help.

my script attached to an box

var explosion : Transform;
function OnCollisionEnter () {
Destroy (gameObject);
var explosionInstance : Transform;
explosionInstance = Instantiate(explosion,transform.position, transform.rotation);

}

ok i watched the video and the guy said make it a prefab. under create click prefab then rename it, after that click your particle and place it in the prefab. then in your heirarchy delete the particle. Now place the prefab into the blank beside explosion when you click on the script from the hierarchy.