grep RFC1918

netstat -rn |grep -v ^10\\.|grep -v ^192.168\\.|grep -E ^172.\(1[6-9]\|2\.\|3[0-1]\)\.
or
netstat -rn |grep -v -E \(^10\\.\|^192.168\\.\|^172.\(1[6-9]\|2\.\|3[0-1]\)\.\|\(S\|link\)\)|sort -n
or
netstat -rn |grep -v -E \(^10\\.\|^192.168\\.\|^172.\(1[6-9]\|2\.\|3[0-1]\)\.\)|sort -n

delete file 'mysql-bin.0000xx'

mysql> flush logs;
will create a brand new mysql-bin.0000xy
mysql> purge binary logs to 'mysql-bin.0000xy';
will purge all logs files before the last.