destroy object when on floor Help

i have a soda can that when u drink it gives health , etc... now when i drop it on the floor i want it to be destroyed. Problem is i have var that says onfloor and works when its off floor and whens its not, but it wont destroy it...

 var isDone : boolean;
 var isOnFloor : boolean;
 var isCurrentGun : boolean;
 var isReady : boolean = true;
 var isPlayed : boolean;
 var healthGiven : boolean;
 var sodaDrinkAudio : AudioClip;
 var playerMovementScript : PlayerMovementScript;
 var health : AdvancedHealth;
 var empty_weapon : GameObject;
 var objectToDestroy : GameObject;
 var Destroyit : boolean;
 
 
 
 function FixedUpdate (){
 
 if(playerMovementScript.currentGun == gameObject)
     {
     isCurrentGun = true;
     isOnFloor = false;
     
     }else{
     
     isCurrentGun = false;
     isOnFloor = true;
     }
 
 
 if(isOnFloor && !isCurrentGun && healthGiven && isPlayed && isDone)
 {
     
     Destroyit = true;
     
     }
 }
 
 
 
     
     
     
 
 
 
 
 
 
 function Update () {
 
     
     
     
     
     
     if(Input.GetKeyDown("u") && isReady && !healthGiven && !isPlayed && playerMovementScript.currentGun == gameObject)
     {
     healthGiven = true;
     isPlayed = true;
     
     
     if(healthGiven && isPlayed)
     {
     isReady = false;
     giveHealthSoda();
     audio.PlayOneShot(sodaDrinkAudio);
     
     }
 
     
     
     
     
 }
 }
     
     
 
     
 
     
 function giveHealthSoda () {
     
     yield WaitForSeconds(5);
     health.maxHealth += 1;
     yield WaitForSeconds(.08);
     health.maxHealth += 1;
     yield WaitForSeconds(.08);
     health.maxHealth += 1;
     yield WaitForSeconds(.08);
     health.maxHealth += 1;
     yield WaitForSeconds(.08);
     health.maxHealth += 1;
     yield WaitForSeconds(.08);
     health.maxHealth += 1;
     yield WaitForSeconds(.08);
     health.maxHealth += 1;
     yield WaitForSeconds(.08);
     health.maxHealth += 1;
     yield WaitForSeconds(.05);
     isDone = true;
     yield WaitForSeconds(3.0);
     
     
     if (Destroyit == true)
     {
     yield WaitForSeconds (3.0);
     Destroy (objectToDestroy);
     }
     
     
 
 
 
 
 
 }