((جَعَلَ النَّبِيُّ صلى الله عليه وسلم عِنْدَ مَوْتِهِ يُدْخِلُ يَدَيْهِ فِي الْمَاءِ فَيَمْسَحُ بِهِمَا وَجْهَهُ، وَيَقُولُ: لاَ إِلَهَ إِلاَّ اللَّهُ إِنَّ لِلْمَوْتِ سَكَرَاتٍ)).
'Aa.ishah (radhi-yAllaahu 'anhaa) related that The Prophet (sal-Allaahu 'alayhe wa sallam) [during his illness in which he passed away] would dip his hands in water and then he would wipe his face and say: ‘None has the right to be worshipped except Allaah, death does indeed contain agony.’
Al-Bukhari, cf. Al-Asqalani, Fathul-Bari 8/144. The Hadith also mention him using the Siivak (tooth stick).