The kdestroy utility destroys the user's active
Kerberos authorization tickets by writing zeros to the specified credentials
cache that contains them. If the credentials cache is not specified, the
default credentials cache is destroyed. If the credentials cache does not
exist, kdestroy displays a message to that effect.
After overwriting the cache, kdestroy removes the
cache from the system. The utility displays a message indicating the success
or failure of the operation. If kdestroy is unable to
destroy the cache, it will warn you by making your terminal beep.
If desired, you can place the kdestroy command
in your .logout file so that your tickets are destroyed
automatically when you logout.