Hadith 384
وَعَنْهَا قَالَتْ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَسْتَاكُ فَيُعْطِينِي السِّوَاكَ لِأَغْسِلَهُ فَأَبْدَأُ بِهِ فَأَسْتَاكُ ثُمَّ أَغْسِلُهُ وَأَدْفَعُهُ إِلَيْهِ. رَوَاهُ أَبُو دَاوُد
She also said, “The Prophet was accustomed to use the tooth-stick and then give it to me to wash it. I would first use it myself, then wash it and hand it to him.” Abu Dawud transmitted it.