"Heh. Ten points? Guess I better step up my game." He grinned a bit at that. "Fair. And all right, salt will work. Don't try this on your own without understanding the amounts to use. The wrong amount could cause a dangerous situation. Just sprinkle it, no more than two pinches between your fingers for now, since our fire is pretty small. Now, the real question, what color do you think the fire will turn?"
Senku held up a finger in thought. "Keep in mind what I mentioned about fire earlier and that salt is sodium chloride, basically. What else has chloride? What else has sodium? Given that you're a wizard and don't depend on science, I might forgive you for not knowing, but we'll make a scientist out of you yet."