Clamp rotation of a GameObject

Hi all, I've looked into it here and other places, but I can't seem to work it out. When I click my mouse, the object rotates on Y, but I'm trying to work out how to limit the rotation, I've been using Mathf.Clamp but I'm not having much luck. Can anyone point me in the right direction? I'm coding in C#.

     void Update () {
         if (Input.GetMouseButton (0)) {
                         Debug.Log ("Input recieved");
                         transform.Rotate (Vector3.up * Time.deltaTime * moveSpeed);
                 }
 
         if (Input.GetMouseButton (1)){
                         Debug.Log ("Input recieved");
                         transform.Rotate (Vector3.up * Time.deltaTime * -moveSpeed);
                 }
 
         transform.rotation = new Vector3(Mathf.Clamp(Transform.rotation.y, -90, 90));
 }
 }