After you have created an instance of a Component Object Model (COM) object, you can delete the object when it is no longer being used. Deleting the object frees system resources.
Each object has a counter that tracks the number of variables that refer to it. Only when this counter equals 0 can the object be deleted. So, to delete an object you must destroy all variables that refer to that object. For example, in the code below, ob1 is a variable that refers to ob:
ob1 = ob
ob = Nothing ! object not destroyed
ob1 = Nothing ! object destroyed
Note that all objects are automatically deleted when the application ends or when the program is aborted.