How can I detect a collision between two clones and delete them both?

Questions & Answers
1

When there is two coin clones in the same position and my player goes on top of them, I want it to only add to my coins value by 1 but it does it by how many coins are in the same position. Any help?

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Coin : MonoBehaviour
{
    [SerializeField]
    private PlayerController player;
    private bool collectCoin;

    void Start()
    {
        player = GameObject.Find("Player").GetComponent<PlayerController>();
    }

    private void OnTriggerEnter(Collider other) {
        if (other.CompareTag("Player") && collectCoin == false) {

            collectCoin = true;
            player.coins++;
            collectCoin = false;

            Destroy(this.gameObject);
        }
        //one clone colliding with the other ones in the same position and destroying each other
        if (other.transform.position == gameObject.transform.position) {
            Destroy(other.gameObject);
            Destroy(this.gameObject);
        }
    }
}
2

Use a bool to detect when it’s triggered and use a coroutine to add to the value.

Use this on the coin.

private void OnTriggerEnter(Collider other) {
    if (other.CompareTag("Player"){
        player.GetComponent<PlayerScript>().addCoin = true;
        player.GetComponent<PlayerScript>().StartCoroutine("CollectCoin");
        Destroy(gameObject);
    }
}

and this on the player.

IEnumerator CollectCoin(){
    yield return new WaitForEndOfFrame();
    if(addCoin){
        coins++;
        addCoin = false;
    }
}