ObjectManager.Unregister C# (CSharp) Method

    public static void Unregister(string id)
    {
        //Debug.Log ("Unregistering " + id);
        objects.Remove(id);
    }

    void convert(GameObject first, GameObject second)
    {
        string firstID = ObjectManager.GetID(first);

        ObjectManager.Unregister(firstID);
        GameObject crate = (Instantiate(second, first.transform.position, first.transform.rotation) as GameObject);

        ObjectManager.Register(crate, firstID);

        crate.transform.position =
            new Vector3(crate.transform.position.x, Terrain.activeTerrain.SampleHeight(crate.transform.position), crate.transform.position.z);

        Destroy(first);
    }