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