How can one purify the soul, the home, and clothing after a dog has been present in the house for one day without moving, and can the soil used for purification be street sand, and is normal ablution (wudu') sufficient for prayer thereafter?

A group of scholars has concluded that the sweat of a dog and what emanates from its outer surface are pure, while its saliva and what emanates from its inner parts are impure. It is obligatory to purify anything that has been touched by a dog's saliva, urine, or feces. If it is land, it suffices to pour water over it until it covers the impure spot. If it is something else, it must be washed seven times, one of which is with earth or soap or the like. Anything whose impurity is doubtful is considered pure by default.