user3551: What kind of practices can one do to neutralise a hateful temperament? 
Can i please have specific techniques.Thank you.
Edit:
By temperament i mean a character or habit.

user254: If a 'hateful temperament' means like 'ill-will', one source says that an antidote is metta meditation.
Ill will (vyapada) says,

The antidote to the hindrance of ill will (vyapada) is meditation on loving kindness (metta). Ajahn Brahmavamso states:[web 2]

Ill will is overcome by applying Metta, loving kindness. When it is ill will towards a person, Metta teaches one to see more [etc.]



Alternatively, "hatred" might be seen as a subtype of aversion, i.e. one of the three poisons.
Dvesha (Buddhism) says,

Dvesha (Sanskrit, also dveṣa; Pali: dosa; Tibetan: zhe sdang) - is a Buddhist term that is translated as "aversion", "aggression", "anger", etc. It can be defined as a fear of getting what we don't want, or not getting what we do want.[1] Dvesha (dosa) is identified in the following contexts within the Buddhist teachings:

One of the three poisons within the Mahayana Buddhist tradition.
One of the three unwholesome roots within the Theravada Buddhist tradition
One of the fourteen unwholesome mental factors within the Theravada Abhidharma teachings


Overcoming the kleshas says (or at least, it claims that),

All Buddhist schools teach that through Tranquility (Samatha) meditation the kilesas are pacified, though not eradicated, and through Insight (Vipassana) the true nature of the kilesas and the mind itself is understood. When the empty nature of the Self and the Mind is fully understood, there is no longer a root for the disturbing emotions to be attached to, and the disturbing emotions lose their power to distract the mind.

So if 'metta' doesn't seem to work then perhaps samatha or vipassana might. But I think you've said that you have mostly been practicing samatha, already, in the past?

Apart from these three (metta, samatha, and vipasanna) the only other approach I know of is non-hatred.
Sometimes Buddhism seems to be about, not replacing this with that (e.g. replacing hatred with loving-kindness), but letting go of this and that.
Opposite wholesome qualities lists two opposite qualities, not just one,

adveṣa (non-aggression, lack of hatred); mettā (loving-kindness)

Advesha says,

Advesha (Sanskrit; Pali: adosa; Tibetan Wylie: zhes sdang med pa) is a Buddhist term translated as "non-aggression" or "non-hatred". It is defined as the absence of an aggressive attitude towards someone or something that causes pain.[1][2] It is one of the mental factors within the Abhidharma teachings.
The Abhidharma-samuccaya states:

What is advesha? It is the absence of the intention to harm sentient beings, to quarrel with frustrating situations, and to inflict suffering on those who are the cause of frustration. It functions as a basis for not getting involved with unwholesome behavior.[1]


This version of verse 5 from the start of the Dhammapada says,

Hatred is, indeed, never appeased by hatred in this world. It is appeased only by loving-kindness. This is an ancient law.

The commentary ends with,

They were made to see that hatred could only cause more hatred, and that it could only cease through friendship, understanding and goodwill.

The Pali version though is,

Na hi verena verani
  sammantidha kudacanam
  averena ca sammanti
  esa dhammo sanantano.

There's a word in the first line (verani) meaning 'hatred', and one in the third (averena) which is the opposite or more specifically the negation, 'non-hatred' (the prefix a- seems to mean 'not-' or 'non-' in Pali, as it does also in English).
Some of more literal and less poetic translations of the Dhammapada for example this one say "non-hatred" rather than "loving-kindness".
You might find it easier (or better) to feel non-hatred or rather to not feel hatred: to not 'feel'; or to aim for emptiness and transience (not constructing a self who feels hateful, not holding on to hate if it arises), than to aim for artificial loving-kindness.
I think that goes with some of the other Buddhist teaching (especially the early and non-explicitly-altruistic teaching) which seem IMO to describe other concepts too such as 'nirvana' for example (or the third noble truth) as a bit of negation or a zero, for example as an "unbinding" 

user295: The root of this is in the perception:

you have perception of something which does not hold which you react to. You deluded by the perception and react with aversion or attachment

If this is directed at a person:

you have a perception of your self as an entity and another person as an entity
in you entity view you attach or associate certain attributes with the entity, which you perceive positively or negatively and react to your perception
you have an entity view of your self and the other person to which you attach certain attributes, you measure what these attributes are favourably or unfavourably using some perceived yard stick and hence react to the measurement

Then temperament arises as you do more of the above this becomes dominating habit.
So what need to be done is to address the above:

Break the habit

When something negative happens, realise it, if it is intense and overpowering try to replace it with the opposite perception or view, if not ignore it by paying attention to something else like the breath, then try to calm the fabrication by looking at the sensation (passive approach) or by calming the breath and creating pleasant sensation in the body (active approach - faster), if it does not work brining you attention to the upper palate touching it with the tongue
Make it a habit to cultivate Metta

Changing the polarity of perception 

You mental reaction will always associated with some sensation so do not cling or react to the sensation or generating reinforcing thoughts and views which might strengthen the perception (opposite thoughts are OK if it is over powering)

Getting rid of perception altogether

Through insight meditation, especially by strengthening your awareness of what ever that comes to your consciousness, diluting your perception and views, cultivating conducive view and perception aimed at reducing the polarity leading to the cessation of perception and the aggregates, calming the fabrications by not creating new fabrication and / or actively reducing them, etc. 



user471: The solution is to use Metta (loving kindness). For canonical description of Metta, please see the Karaniya Metta Sutta, Metta Sutta and the Mettanisamsa Sutta.
Information on how to practise Metta can be found here and here. These are quite specific and written by Ven. Dhammarakkhita and Ven. Buddharakkhita. These are too long to quote here.
Hateful temperament is part of "ill will", one of the five hindrances (also here) to meditation and practice. Ajahn Brahmavamso explains in this essay:

Ill will refers to the desire to punish, hurt or destroy. It includes
  sheer hatred of a person, or even a situation, and it can generate so
  much energy that it is both seductive and addictive. At the time, it
  always appears justified for such is its power that it easily corrupts
  our ability to judge fairly. It also includes ill will towards
  oneself, otherwise known as guilt, which denies oneself any
  possibility of happiness. In meditation, ill will can appear as
  dislike towards the meditation object itself, rejecting it so that
  one's attention is forced to wander elsewhere.
The Lord Buddha likened ill will to being sick. Just as sickness
  denies one the freedom and happiness of health, so ill will denies one
  the freedom and happiness of peace.
Ill will is overcome by applying Metta, loving kindness. When it is
  ill will towards a person, Metta teaches one to see more in that
  person than all that which hurts you, to understand why that person
  hurt you (often because they were hurting intensely themselves), and
  encourages one to put aside one's own pain to look with compassion on
  the other. But if this is more than one can do, Metta to oneself leads
  one to refuse to dwell in ill will to that person, so as to stop them
  from hurting you further with the memory of those deeds. Similarly, if
  it is ill will towards oneself, Metta sees more than one's own faults,
  can understand one's own faults, and finds the courage to forgive
  them, learn from their lesson and let them go.


3551: <p>What kind of practices can one do to neutralise a hateful temperament? </p>

<p>Can i please have specific techniques.Thank you.</p>

<p>Edit:</p>

<p>By temperament i mean a character or habit.</p>
 254: <p>If a 'hateful temperament' means like 'ill-will', one source says that an antidote is metta meditation.</p>

<p><a href="http://en.wikipedia.org/wiki/Five_hindrances#Ill_will_.28vyapada.29" rel="nofollow">Ill will (vyapada)</a> says,</p>

<blockquote>
  <p>The antidote to the hindrance of ill will (vyapada) is meditation on loving kindness (metta). Ajahn Brahmavamso states:[web 2]</p>
  
  <blockquote>
    <p>Ill will is overcome by applying Metta, loving kindness. When it is ill will towards a person, Metta teaches one to see more [etc.]</p>
  </blockquote>
</blockquote>

<hr>

<p>Alternatively, "hatred" might be seen as a subtype of aversion, i.e. one of the three poisons.</p>

<p><a href="http://en.wikipedia.org/wiki/Dvesha_(Buddhism)" rel="nofollow">Dvesha (Buddhism)</a> says,</p>

<blockquote>
  <p>Dvesha (Sanskrit, also dveṣa; Pali: dosa; Tibetan: zhe sdang) - is a Buddhist term that is translated as "aversion", "aggression", "anger", etc. It can be defined as a fear of getting what we don't want, or not getting what we do want.[1] Dvesha (dosa) is identified in the following contexts within the Buddhist teachings:</p>
  
  <ul>
  <li>One of the <a href="http://en.wikipedia.org/wiki/Three_poisons_(Buddhism)" rel="nofollow">three poisons</a> within the Mahayana Buddhist tradition.</li>
  <li>One of the <em>three unwholesome roots</em> within the Theravada Buddhist tradition</li>
  <li>One of the <a href="http://en.wikipedia.org/wiki/Mental_factors_(Buddhism)#Fourteen_unwholesome_mental_factors" rel="nofollow">fourteen unwholesome mental factors</a> within the Theravada Abhidharma teachings</li>
  </ul>
</blockquote>

<p><a href="http://en.wikipedia.org/wiki/Kleshas_(Buddhism)#Overcoming_the_kleshas" rel="nofollow">Overcoming the kleshas</a> says (or at least, it claims that),</p>

<blockquote>
  <p>All Buddhist schools teach that through Tranquility (Samatha) meditation the kilesas are pacified, though not eradicated, and through Insight (Vipassana) the true nature of the kilesas and the mind itself is understood. When the empty nature of the Self and the Mind is fully understood, there is no longer a root for the disturbing emotions to be attached to, and the disturbing emotions lose their power to distract the mind.</p>
</blockquote>

<p>So if 'metta' doesn't seem to work then perhaps samatha or vipassana might. But I think you've said that you have mostly been practicing samatha, already, in the past?</p>

<hr>

<p>Apart from these three (metta, samatha, and vipasanna) the only other approach I know of is non-hatred.</p>

<p>Sometimes Buddhism seems to be about, not replacing this with that (e.g. replacing hatred with loving-kindness), but letting go of this and that.</p>

<p><a href="http://en.wikipedia.org/wiki/Three_poisons_%28Buddhism%29#Opposite_wholesome_qualities" rel="nofollow">Opposite wholesome qualities</a> lists two opposite qualities, not just one,</p>

<blockquote>
  <p><a href="http://en.wikipedia.org/wiki/Adve%E1%B9%A3a" rel="nofollow">adveṣa</a> (non-aggression, lack of hatred); <a href="http://en.wikipedia.org/wiki/Mett%C4%81" rel="nofollow">mettā</a> (loving-kindness)</p>
</blockquote>

<p><a href="http://en.wikipedia.org/wiki/Advesha" rel="nofollow">Advesha</a> says,</p>

<blockquote>
  <p>Advesha (Sanskrit; Pali: adosa; Tibetan Wylie: zhes sdang med pa) is a Buddhist term translated as "non-aggression" or "non-hatred". It is defined as the absence of an aggressive attitude towards someone or something that causes pain.[1][2] It is one of the mental factors within the Abhidharma teachings.</p>
  
  <p>The Abhidharma-samuccaya states:</p>
  
  <blockquote>
    <p>What is advesha? It is the absence of the intention to harm sentient beings, to quarrel with frustrating situations, and to inflict suffering on those who are the cause of frustration. It functions as a basis for not getting involved with unwholesome behavior.[1]</p>
  </blockquote>
</blockquote>

<p><a href="http://www.tipitaka.net/tipitaka/dhp/verseload.php?verse=005" rel="nofollow">This version of verse 5 from the start of the Dhammapada</a> says,</p>

<blockquote>
  <p>Hatred is, indeed, never appeased by hatred in this world. It is appeased only by loving-kindness. This is an ancient law.</p>
</blockquote>

<p>The commentary ends with,</p>

<blockquote>
  <p>They were made to see that hatred could only cause more hatred, and that it could only cease through friendship, understanding and goodwill.</p>
</blockquote>

<p>The Pali version though is,</p>

<blockquote>
  <p>Na hi verena verani<br>
  sammantidha kudacanam<br>
  averena ca sammanti<br>
  esa dhammo sanantano.</p>
</blockquote>

<p>There's a word in the first line (<em>verani</em>) meaning 'hatred', and one in the third (<em>averena</em>) which is the opposite or more specifically the negation, 'non-hatred' (the prefix <code>a-</code> seems to mean 'not-' or 'non-' in Pali, as it does also in English).</p>

<p>Some of more literal and less poetic translations of the Dhammapada <a href="http://www.accesstoinsight.org/tipitaka/kn/dhp/dhp.01.budd.html" rel="nofollow">for example this one</a> say "non-hatred" rather than "loving-kindness".</p>

<p>You might find it easier (or better) to feel non-hatred or rather to not feel hatred: to not 'feel'; or to aim for emptiness and transience (not constructing a self who feels hateful, not holding on to hate if it arises), than to aim for artificial loving-kindness.</p>

<p>I think that goes with some of the other Buddhist teaching (especially the early and non-explicitly-altruistic teaching) which seem IMO to describe other concepts too such as 'nirvana' for example (or the third noble truth) as a bit of negation or a zero, for example as an "unbinding" </p>
 295: <p>The root of this is in the perception:</p>

<ul>
<li>you have perception of something which does not hold which you react to. You deluded by the perception and react with aversion or attachment</li>
</ul>

<p>If this is directed at a person:</p>

<ul>
<li>you have a perception of your self as an entity and another person as an entity</li>
<li>in you entity view you attach or associate certain attributes with the entity, which you perceive positively or negatively and react to your perception</li>
<li>you have an entity view of your self and the other person to which you attach certain attributes, you measure what these attributes are favourably or unfavourably using some perceived yard stick and hence react to the measurement</li>
</ul>

<p>Then temperament arises as you do more of the above this becomes dominating habit.</p>

<p>So what need to be done is to address the above:</p>

<ul>
<li>Break the habit
<ul>
<li>When something negative happens, realise it, if it is intense and overpowering try to replace it with the opposite perception or view, if not ignore it by paying attention to something else like the breath, then try to calm the fabrication by looking at the sensation (passive approach) or by calming the breath and creating pleasant sensation in the body (active approach - faster), if it does not work brining you attention to the upper palate touching it with the tongue</li>
<li>Make it a habit to cultivate Metta</li>
</ul></li>
<li>Changing the polarity of perception 
<ul>
<li>You mental reaction will always associated with some sensation so do not cling or react to the sensation or generating reinforcing thoughts and views which might strengthen the perception (opposite thoughts are OK if it is over powering)</li>
</ul></li>
<li>Getting rid of perception altogether
<ul>
<li>Through insight meditation, especially by strengthening your awareness of what ever that comes to your consciousness, diluting your perception and views, cultivating conducive view and perception aimed at reducing the polarity leading to the cessation of perception and the aggregates, calming the fabrications by not creating new fabrication and / or actively reducing them, etc. </li>
</ul></li>
</ul>
 471: <p>The solution is to use <a href="http://en.wikipedia.org/wiki/Mett%C4%81" rel="nofollow">Metta</a> (loving kindness). For canonical description of Metta, please see the <a href="http://www.accesstoinsight.org/tipitaka/kn/snp/snp.1.08.than.html" rel="nofollow">Karaniya Metta Sutta</a>, <a href="http://www.accesstoinsight.org/tipitaka/an/an04/an04.125.than.html" rel="nofollow">Metta Sutta</a> and the <a href="http://www.accesstoinsight.org/tipitaka/an/an11/an11.016.piya.html" rel="nofollow">Mettanisamsa Sutta</a>.</p>

<p>Information on how to practise Metta can be found <a href="http://www.buddhanet.net/pdf_file/scrn_metta.pdf" rel="nofollow">here</a> and <a href="http://www.accesstoinsight.org/lib/authors/buddharakkhita/wheel365.html" rel="nofollow">here</a>. These are quite specific and written by Ven. Dhammarakkhita and Ven. Buddharakkhita. These are too long to quote here.</p>

<p>Hateful temperament is part of "ill will", one of <a href="http://en.wikipedia.org/wiki/Five_hindrances" rel="nofollow">the five hindrances</a> (also <a href="http://insightmeditationcenter.org/articles/FiveHindrances.pdf" rel="nofollow">here</a>) to meditation and practice. Ajahn Brahmavamso explains in <a href="http://www.budsas.org/ebud/ebmed051.htm" rel="nofollow">this essay</a>:</p>

<blockquote>
  <p>Ill will refers to the desire to punish, hurt or destroy. <strong>It includes
  sheer hatred of a person, or even a situation</strong>, and it can generate so
  much energy that it is both seductive and addictive. At the time, it
  always appears justified for such is its power that it easily corrupts
  our ability to judge fairly. It also includes ill will towards
  oneself, otherwise known as guilt, which denies oneself any
  possibility of happiness. In meditation, ill will can appear as
  dislike towards the meditation object itself, rejecting it so that
  one's attention is forced to wander elsewhere.</p>
  
  <p>The Lord Buddha likened ill will to being sick. Just as sickness
  denies one the freedom and happiness of health, so ill will denies one
  the freedom and happiness of peace.</p>
  
  <p><strong>Ill will is overcome by applying Metta, loving kindness</strong>. When it is
  ill will towards a person, Metta teaches one to see more in that
  person than all that which hurts you, to understand why that person
  hurt you (often because they were hurting intensely themselves), and
  encourages one to put aside one's own pain to look with compassion on
  the other. But if this is more than one can do, Metta to oneself leads
  one to refuse to dwell in ill will to that person, so as to stop them
  from hurting you further with the memory of those deeds. Similarly, if
  it is ill will towards oneself, Metta sees more than one's own faults,
  can understand one's own faults, and finds the courage to forgive
  them, learn from their lesson and let them go.</p>
</blockquote>
