Noorah is composed of calcium and arsenic and was used to remove hair. It would be applied to the place, left for a while then washed off, and the hair would come off with it. See: al-Qamoos al-Fiqhi (1/363) and Zaad al-Ma’aad (4/364).
With regard to the Messenger (peace and blessings of Allaah be upon him) using it, that was narrated in some ahaadeeth, but they are all da’eef (weak) and are not saheeh (sound).
Ibn Maajah (3751) narrated from Umm Salamah (may Allaah be pleased with her) that the Prophet (peace and blessings of Allaah be upon him) used to apply noorah (for removing hair).
This hadeeth was classed as da’eef by al-Busayri in Misbaah al-Zujaajah and by al-Albaani in Da’eef Sunan Ibn Maajah and by Shu’ayb al-Arna’oot in Tahqeeq Zaad al-Ma’aad.
Ibn ‘Asaakir narrated from the hadeeth of Ibn ‘Umar that the Prophet (peace and blessings of Allaah be upon him) used to apply noorah every month and clip his nails every fifteen days.
This was classed as da’eef by al-Albaani in Da’eef al-Jaami’ al-Sagheer (no. 4536).
Conclusion: there is no saheeh hadeeth to indicate that the Prophet (peace and blessings of Allaah be upon him) used it, but there is nothing wrong with using it or using anything else to remove hair, so long as it is not harmful. But shaving is better, because it is mentioned in the Sunnah, and the majority of fuqaha’ are of the view that shaving is better.
See: al-Mawsoo’ah al-Fiqhiyyah (14/83).
And Allaah knows best.