Praise
be to Allaah.
It is narrated in a saheeh hadeeth
that the Prophet
(peace and blessings of Allaah be upon him) said: “None of you should
touch his penis with his right hand when he is urinating, or wipe himself
with his right hand after relieving oneself, or breathe into the vessel
(from which he drinks).” (Narrated by Muslim, al-Tahaarah, 392)
Al-Nawawi said: The right
hand is not to be used for any of those things for cleaning oneself
after relieving oneself (i.e., either urinating or defecating).
On this basis, one has to use
the left hand for removing najaasah (impurity), no matter how it is
used, whether one uses the entire hand or part of it. The aim is to
remove the najaasah from the body. The issue here is flexible; what
matters is to avoid using the right hand in removing dirt. And Allaah
knows best.
See
also Question # 2532