Purging failed transactions from an Oracle DB

From time to time you may find yourself in a situation where a database which connects to your Oracle database loses the connection, but your database thinks that it is still connected and you can leverage MOS document "How to Purge a Distributed Transaction from a Database" from article ID 159377.1 to investigate the tables DBA_2PC_PENDING and DBA_2PC_NEIGHBORS with how to nuke off the sessions as well!