Shampoo cleans and conditioner makes it soft. Or rather shampoo removes all your natural oil and conditioner adds back some oil. I personally use baking soda to remove grease and apple cider vinegar to clear our the excess baking soda. It's cheap as fuck and foes a better job than any other shampoo I have used. Baking soda also works great as a deodoriser and acv is a great antibacterial/antifungal to get rid of rashes, itches, lice and scalp problems. If you can't stand the smell of acv add some cinnamon to it. Those are generally very useful items to have if you are creating a bug out kit, better than saving some shit shampoo