Destroy declaration but not game object

Hi. When i move mouse and my raycast give info that item is pickable i put him info item, by simply

public Rigidbody item;
RaycastHit hit;

item = hit.collider.GetComponent<Rigidbody>();

And i see what item im holding in unity window.

After i relise item (drop or throw) i want to make item unsigned again so i can pick other object/oher cube

(in unity “Item None (Rigidbody)” )

how can i unassinged item again? browse on internet but could find answer

Have you simply tried item = null?

private Rigidbody item; // we dont need to store item in inspector
Raycast hit;

if(hit.collider.GetComponent<Rigidbody>() != null){
    item = hit.collider.GetComponent<Rigidbody>(); 
}

Try this. You check if object you hit has rigidbody, then locally you assaign item and it should overwrite next time.