Cant delete prefab clones

hi i have a simple game where prefab obstacles appear on screen i would like to the clones of the prefabs delete after a few seconds. how would i do this? here is the script ive made any help would be highly appreciated thanks

 public GameObject track;
 public bool spawned;

 public GameObject Gold;

 public GameObject Player;

 public float amountOfGold;

 public float minX, maxX;

 public GameObject obstacle;

 public float amountOfObstacle;


 public void Start()

 {
     Player = GameObject.FindWithTag("Player");

     for (int i = 0; i < amountOfObstacle; i++)
     {
         float xAxis, yAxis;
         xAxis = Random.Range(minX, maxX);
         yAxis = Random.Range(Player.transform.localPosition.y - 20, Player.transform.localPosition.y - 50);
         Vector3 pos = new Vector3(xAxis, yAxis, 0);
         Instantiate(obstacle.transform, pos, Quaternion.identity);
     }
 
     Player = GameObject.FindWithTag("Player");

     for (int i = 0; i < amountOfGold; i++)

     {
         float xAxis, yAxis;
         xAxis = Random.Range(minX, maxX);
         yAxis = Random.Range(Player.transform.localPosition.y - 20, Player.transform.localPosition.y - 50);
         Vector3 pos = new Vector3(xAxis, yAxis, 0);
         Instantiate(Gold.transform, pos, Quaternion.identity);
     }
 }
 void OnTriggerEnter(Collider other)
 {
     if (other.tag == "Player" && !spawned)

     {
         Vector3 pos = new Vector3(transform.parent.position.x, (transform.parent.position.y - 20f), transform.parent.position.z);
         Instantiate(track.transform, pos, transform.parent.rotation);
         spawned = true;

     
         Destroy(GameObject.Find(Gold.name + "(Clone)"), 1f);
         Destroy(GameObject.Find(obstacle.name + "(Clone)"), 1f);
     }
 }

}