def METHOD_NAME( cls):
    """Clean up junk which might be left over from old runs;
       do fast stuff before slow dp and link removal!"""
    info( "*** Removing excess controllers/ofprotocols/ofdatapaths/"
          "pings/noxes\n" )
    zombies = ( 'controller ofprotocol ofdatapath ping nox_core '
                'lt-nox_core ovs-openflowd ovs-controller '
                'ovs-testcontroller udpbwtest mnexec ivs ryu-manager ' )
    # Note: real zombie processes can't actually be killed, since they
    # are already (un)dead. Then again,
    # you can't connect to them either, so they're mostly harmless.
    # Send SIGTERM first to give processes a chance to shutdown cleanly.
    sh( 'killall ' + zombies + ' 2> /dev/null' )
    time.sleep( 1 )
    sh( 'killall -9 ' + zombies + ' 2> /dev/null' )
    # And kill off sudo mnexec
    sh( 'pkill -9 -f "sudo mnexec"')
    info( "*** Removing junk from /tmp\n" )
    sh( 'rm -f /tmp/vconn* /tmp/vlogs* /tmp/*.out /tmp/*.log' )
    info( "*** Removing old X11 tunnels\n" )
    cleanUpScreens()
    info( "*** Removing excess kernel datapaths\n" )
    dps = sh( "ps ax | egrep -o 'dp[0-9]+' | sed 's/dp/nl:/'"
              ).splitlines()
    for dp in dps:
        if dp:
            sh( 'dpctl deldp ' + dp )
    info( "***  Removing OVS datapaths\n" )
    dps = sh("ovs-vsctl --timeout=1 list-br").strip().splitlines()
    if dps:
        sh( "ovs-vsctl " + " -- ".join( "--if-exists del-br " + dp
                                        for dp in dps if dp ) )
    # And in case the above didn't work...
    dps = sh( "ovs-vsctl --timeout=1 list-br" ).strip().splitlines()
    for dp in dps:
        sh( 'ovs-vsctl del-br ' + dp )
    info( "*** Removing all links of the pattern foo-ethX\n" )
    links = sh( "ip link show | "
                "egrep -o '([-_.[:alnum:]]+-eth[[:digit:]]+)'"
                ).splitlines()
    # Delete blocks of links
    n = 1000  # chunk size
    for i in range( 0, len( links ), n ):
        cmd = ';'.join( 'ip link del %s' % link
                         for link in links[ i : i + n ] )
        sh( '( %s ) 2> /dev/null' % cmd )
    if 'tap9' in sh( 'ip link show' ):
        info( "*** Removing tap9 - assuming it's from cluster edition\n" )
        sh( 'ip link del tap9' )
    info( "*** Killing stale mininet node processes\n" )
    killprocs( 'mininet:' )
    info( "*** Shutting down stale tunnels\n" )
    killprocs( 'Tunnel=Ethernet' )
    killprocs( '.ssh/mn')
    sh( 'rm -f ~/.ssh/mn/*' )
    # Call any additional cleanup code if necessary
    for callback in cls.callbacks:
        callback()
    info( "*** Cleanup complete.\n" )