Destroying Instantiated Obect Problem

So I have this script that when I press t it spawns a wood plank in front of you that you can place down. However I can't get the board to go away when you press the same button. Any ideas on how I could do this? Here's the script:

 if (Input.GetKeyUp("t") && woodAvailable > 0) {
         
             if ( buildingMaterial == true) {
                 
             Destroy(obstacleToBuild);
             buildingMaterial = false;
                 
             }
             
             
             
             if (buildingMaterial == false){
             
             playerPosition = transform.position;
             playerRotation = transform.rotation;
             
             obstacleToBuild = Instantiate(woodPlank, myGamobject.transform.FindChild("Main Camera").position + 3f * Vector3.forward, myGamobject.transform.FindChild("Main Camera").rotation) as GameObject;
             obstacleToBuild.transform.parent = myGamobject.transform.FindChild("Main Camera");
             buildingMaterial = true;
         
                 
             }
         
         
         }