Q1) What is Mano Nasha and Mano laya ? – No mind state.
Mano nasha means destruction of ignorance in mind. The ego identifies with the body forgetting its SELF (Brahman) which is its real nature. Mind goes after the apparent reality (mithya) of world. This is called avidya or ignorance.
When the ignorance drops – there is a cognitive shift from self identity with the body to SELF Awareness. Realization that “I AM Brahman – I am pure consciousness . Sat-chit-ananda” . The world is a not real but unreal (mithya). This is a state of no mind since mind has taken the form of SELF. This is called mano -nasha. One gets established in a blissful state of Sat-chit-ananda.
There is cognitive realization that “Brahma Satya, Jagat, mithya, jivo brahmaiva na aparaha. – Brahman alone is Reality. World is unreal. Individual consciousness Jiva is Brahman only. World is nothing but Brahman appearing in different name and forms.
On the other hand, during deep sleep, meditation, samadhi, mind goes to subtle state. There is peace and bliss in this state also. But this is a temporary state. Ignorance is not dropped. Hence mind returns back to its original condition.
Q2). How to achieve mano-nasha ?
Mano nasha can only come through Jnana. When rope is mistaken for snake, it is called error in perception (adhyasa). Through knowledge only the superimposition of snake and rope can be removed.
Similarly, jiva is a combination of reflected consciousness (chidabhasa) and mind. Reflected consciousness is same as original consciousness. This is a combination of satya (reflected consciousness) and mithya ( material nature – mind). The jiva identifies itself with the body saying “I AM body”. Here I AM consciousness-existence principle due to reflected consciousness which is satya. Body is material (jada) – unreal (mithya). The realization I AM not body – I AM BRAHMAN leads to mano nasha.
For this Viveka and vairagya are needed. Discrimination between real – unreal ( sathya and mithya) and self-non self (atma-anatma) to be done through intellect sharpened based on teaching of vedanta by realized master (guru). The process of Shravana, manana, Nidhidhyasa ( listening to vedanta, contemplation and meditation) has to be followed till realization happens.