Tazkiah (تزكية) is an Arabic-Islamic term alluding to "tazkiyah al-nafs" meaning "sanctification" or "purification of the self". This refers to the process of transforming the nafs (carnal self or desires) from its deplorable state of self-centrality through various spiritual stages towards the level of purity and submission to the Will of Allah.
If the washing machine is connected to the tab water, then it will be Taahir along with all the clothes inside it. If there is no connection with tab water or any Kurr water, and water used is less than Kurr, then Najis cloth will remain Najis unless it is washed and rinsed twice with Taahir water.
There are many books on this subject, but not all of them are translated in English.
One of the well known books which are translated in English is Jami' Al-Sa'adaat by Al-Naraaqi (The Collector of Felicities).
You may also see Mir'aat Al-Rashaad مراة الرشاد by Shaikh Abdullah Al-Mamaqani.