What do you put on a deep cut?

That really depends on how deep it is. Is it bleeding? It is especially red, have a bad odor, or lots of drainage? When in doubt, see your doctor. Meanwhile, you want to keep it clean and moist. Wash is with soap and water. If you have access to saline solution, use that. Otherwise, you can mix a little table salt in some warm water. Rinse the would with the warm salt water. You can use an antibiotic ointment like neosporin. If you dont have that, you can use some petroleum jelly, or vaseline. Dont use much, just a thin layer over the wound. It is best to use a non-stick dressing, but you can use plain gauze. Just remember to keep it clean, moist, and covered. Hope this helps!