To Use A Miswak

Ibni 'Abidin wrote in Radd-ul mukhtar:

It is sunnat-i muakkada [1] to use a miswak when performing an ablution. A hadith-i sharif [2] declares: "The salat which is performed after using a miswak is seventy-fold superior to the salat without a miswak. " A miswak must be straight, as wide as the second small finger, and a span long. The miswak is derived from a branch of the erak (peelo) tree growing in Arabia. [Shaving it about two centimetres from the straight end, you keep this part in water for a couple of hours. When you crush it, it will open like a brush. ] When the erak tree cannot be found, a miswak can be made from an olive branch. You should not make it from a pomegranate branch. If an erak or olive tree cannot be found or if one does not have teeth, the sunnat [3] must be carried out with one's fingers. The miswak has more than thirty advantages, which are written in Tahtawi's Hashiyatu Maraq al-falah. Firstly, it causes one to die with iman [4] in one's last breath. It is makruh [5] for men to chew gum without any 'udhr (strong necessity), even when they are not fasting. Women must use chewing gum when they are not fasting instead of a miswak by intending to do the sunnat.

[1] Sunnat-i muakkada / Sunnat-i huda: Emphatic, practised regularly by our blessed Prophet. They are the shi'âr (symptoms) of the Islamic religion. [That is, they are peculiar to Islam; they do not exist in other religions.] Sunnat-i huda are like i'tikaf in a mosque, calling the azan or iqamat, and performing salat in jama'at. They are the characteristic traits of Islam, properties peculiar to this Ummat. [It is written in Ibni Abidin, at the end of the last volume that circumcision of children is also a sunnat of this kind.] The rawatib, that is, the muakkad sunnats of three of the fard five daily prayers are of this kind, too.
[2] hadith (sharif): i) a saying of the Prophet ('alaihi 's-salam).; al-Hadith ash-sharif: all the hadiths as a whole; ii) 'ilm al-hadith; iii) Books of the hadith ash-sharif. iv) Al-hadith al-qudsi, as-sahih, al-hasan: kinds of hadiths (for which, see Endless Bliss, II).
[3] sunnat: i) act, thing that was, though not commanded by Allahu ta'ala, done and liked by the Prophet ('alaihi 's-salam) as an 'ibada (there is thawab if done, but no sin if omitted, yet it causes sin if continually omitted and disbelief if disliked; the Sunna; i) (with fard) all the sunnas as a whole; ii) (with the Book or Qur'an al-karim) the Hadith ash-sharif; iii) (alone) fiqh, Islam.
[4] iman: faith, belief, beliefs of Islam; kalam, i'tiqad.
[5] makruh: (act, thing) improper, disliked and abstained by the Prophet ('alaihi 's-salam); makruh tahrima: prohibited with much stress.