This one. And its not that hard to clean as per Islam's req. My pants got smelled by a dog before while working, I thought the dog was friendly that's why I did not shoo her off. Later see her nose kinda wet, I went back and dip my pants in some muddy puddle near my house, then wash back with water. Settle.

Nothing special. As long as you're confident there's no other animal poop in the sand/dirt, you can mix it up with clean water and pour it on the place touched by any wet part of the dog. Then just wash the whole thing off with clean water. Pretty simple.

Any dirt or sand will do as long as its "clean" (no other poop in there before)