It is better to substitute good thoughts for the bad and cleanse the mind of all evil by dwelling on righteous deeds and holy thoughts. Forget the things that you do not want to remember. Bring to memory only those things that are worth remembering. That is the sane way to achieve spiritual progress.
(From : Sai Veda, The Word of God, sayings of Bhagavan Sri Sathya Sai Baba)