For some reason i can't clear my UI Text with something.text = ""; or " ";

Sp basically down bellow is a full code of script, problem is that i tried putting NightReportText.text = " "; everywhere to clear the Text before starting or after finishing StartCoroutine. This script is activated with button, when button is activated => nCanvas.enabled = true; and when script is finished nCanvas.enabled = false; but when i try activating button 2nd time text is the old one from first activation and won't change.

using UnityEngine; using System.Collections; using UnityEngine.UI; using UnityEngine.SceneManagement;

 public class nightScript : sceneScript {
 
     public Text NightReportText;
     //private string reportValue;
 
     // Use this for initialization
     void Start () 
     {
         NightReportText = NightReportText.GetComponent<Text> ();
         StartCoroutine (Wait ());
     }
 
     IEnumerator Wait()
     {
         yield return new WaitForSecondsRealtime (1);
         NightReportText.text = "" + Random.Range (1, 300);
         yield return new WaitForSecondsRealtime (2);
         NightReportText.text = NightReportText.text + "\n" + Random.Range (1, 300);
         yield return new WaitForSecondsRealtime (2);
         NightReportText.text = NightReportText.text + "\n" + Random.Range (1, 300);
         yield return new WaitForSecondsRealtime (2);
         NightReportText.text = NightReportText.text + "\n" + Random.Range (1, 300);
         yield return new WaitForSecondsRealtime (2);
         NightReportText.text = NightReportText.text + "\n" + Random.Range (1, 300);
         yield return new WaitForSecondsRealtime (2);
         NightReportText.text = NightReportText.text + "\n" + Random.Range (1, 300);
         yield return new WaitForSecondsRealtime (2);
 
         nCanvas.enabled = false;
     }
 }