The purification practices found within Buddhism are not unlike the practices applied in many other religions. The most essential mental factor that one requires is sincerity or honesty with oneself. When one wants to purify past negative karma, one has to do some action with the correct motivation.
This is summarised in the following Four Powers of Purification:
1. Power of the Object: One should practice thinking of all sentient beings one may have hurt. Traditionally, one remembers all sentient beings and the Three Jewels of Refuge (Buddha, Dharma and Sangha), by generating compassion for all sentient beings and taking refuge.
2. Power of Regret: This should not be senseless guilt or self-recrimination, which are said to be useless emotional torture. What is intended here is to examine oneself and one's actions and to recognise that negative actions done in the past were very unwise.
3. Power of Promise: As a logical consequence of the above, one should promise not to repeat these negative actions. It is good if one can promise to avoid a negative behaviour for a specific time, or at least promise that one will put effort in avoiding repetition. Not being honest at this stage makes the practice useless or even harmful to oneself.
4. Power of Practice: Basically any positive action with a good motivation can be used as practice. Traditionally in Buddhism, one can practice e.g. making prostrations (throwing oneself to the floor - as a means to destroy pride), making offerings (to counteract greed), reading Buddhist texts (to counteract ignorance and negative thoughts), reciting mantras etc.
 
It is often explained that one needs to clear a field by purifying it from rocks and weeds, then planting seeds by study and meditation, giving water and fertiliser by doing positive actions, and automatically new harvest will grow.

PRACTICAL CONSEQUENCES

OF KARMA

"What fisherman looks for water in dry, dead riverbeds?
He who hopes for spiritual progress, but cultivates neither wisdom nor merit."
His Holiness the 7th Dalai Lama, from 'Songs of spiritual change' translated by Glenn Mullin.

To begin with, I need to understand that I cannot immediately change my present situation, but I should understand that:
- The reason why I am experiencing this is only due to my own actions in the past, my mind filled with delusions or positive thoughts, and the right circumstances for the karma to ripen.
- I can chose to have a selfish reaction to my situation and create my own suffering in the future.
- I can chose to have a reaction considering others' welfare and create happiness for myself as well in the future.
- If I react without thinking, it is easy to create negative results for the future, and even make that a habit.
- The others whom I like to blame for hurting me, are merely the circumstances that make my negative karma ripen.
- Understanding karma means that I have full responsibility for everything that happens to me in the past, present and future.
- Positive thinking and acting will do others and myself much more good than being negative and acting that way.

"Karma is not something complicated or philosophical.
Karma means watching your body, watching your mouth, and watching your mind.
Trying to keep these three doors as pure as possible is the practice of karma."
Lama Thubten Yeshe, "The Bliss of Inner Fire"

FATE IS IN OUR HANDS - A PARABLE

In a time long past, there was an old monk who, through diligent practice, had attained a certain degree of spiritual penetration.
He had a young novice who was about eight years old. One day the monk looked at the boy's face and saw there that he would die within the next few months. Saddened by this, he told the boy to take a long holiday and go and visit his parents. 'Take your time,' said the monk. 'Don't hurry back.' For he felt the boy should be with his family when he died.
Three months later, to his astonishment, the monk saw the boy walking back up the mountain. When he arrived he looked intently at his face and saw that they boy would now live to a ripe old age.
'Tell me everything that happened while you were away,' said the monk. So the boy started to tell of his journey down from the mountain. He told of villages and towns he passed through, of rivers forded and mountains climbed.
Then he told how one day he came upon a stream in flood. He noticed, as he tried to pick his way across the flowing stream, that a colony of ants had become trapped on a small island formed by the flooding stream. Moved by compassion for these poor creatures, he took a branch of a tree and laid it across one flow of the stream until it touched the little island. As the ants made their way across, the boy held the branch steady, until he was sure all the ants had escaped to dry land. Then he went on his way. 'So,' thought the old monk to himself, 'that is why the gods have lengthened his days.'