From Sahih Muslim (Hadith 653):
Ibn Mughaffal reported:The Messenger of Allah (ﷺ) ordered killing of the dogs, and then said: What about them, i. e. about other dogs? and then granted concession (to keep) the dog for hunting and the dog 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
Reference: Muslim 653