The Prophet (sal Allaahu alayhi wa sallam) said: The purification of the utensil belonging to any one of you, after it has been licked by a dog, consists of washing it seven times, using sand in the first instance. Abu Dawud said : A similar tradition has been narrated by Abu Ayyub and Habib b. al-Shahid on the authority of Muhammad.  

عَنِ النَّبِيِّ ﷺ قَالَ طُهُورُ إِنَاءِ أَحَدِكُمْ إِذَا وَلَغَ فِيهِ الْكَلْبُ أَنْ يُغْسَلَ سَبْعَ مِرَارٍ أُولاَهُنَّ بِتُرَابٍ  

"If the cat licks (a utensil), it should be washed once."  

عَنْ أَبِي هُرَيْرَةَ بِمَعْنَاهُ وَلَمْ يَرْفَعَاهُ زَادَ وَإِذَا وَلَغَ الْهِرُّ غُسِلَ مَرَّةً  

The Prophet (sal Allaahu alayhi wa sallam) as saying : When a dog licks a (thing contained in a) utensil you must wash it seven times, using earth (sand) for the seventh time. Abu Dawud said : This tradition has been transmitted by another chain of narrators in which there is no mention of earth.  

أَنَّ نَبِيَّ اللَّهِ ﷺ قَالَ إِذَا وَلَغَ الْكَلْبُ فِي الإِنَاءِ فَاغْسِلُوهُ سَبْعَ مَرَّاتٍ السَّابِعَةُ بِالتُّرَابِ  

The Messenger of Allaah (sal Allaahu alayhi wa sallam) ordered the killing of the dogs, and then said: Why are they (people) after them (dogs)? and then granted permission (to keep) for hunting and for (the security) of the herd, and said : When the dog licks the utensil wash it seven times, and rub it with earth the eighth time. Abu Dawud said : Ibn Mughaffal narrated in a similar way.  

أَنَّ رَسُولَ اللَّهِ ﷺ أَمَرَ بِقَتْلِ الْكِلاَبِ ثُمَّ قَالَ مَا لَهُمْ وَلَهَا فَرَخَّصَ فِي كَلْبِ الصَّيْدِ وَفِي كَلْبِ الْغَنَمِ وَقَالَ إِذَا وَلَغَ الْكَلْبُ فِي الإِنَاءِ فَاغْسِلُوهُ سَبْعَ مِرَارٍ وَالثَّامِنَةُ عَفِّرُوهُ بِالتُّرَابِ