Yuu bites a thumbnail for a moment, trying to figure this out, then seems to come to some sort of realization. With a slight smile, he digs a piece of candy out of his pocket. This stuff will help him solve the mystery. Obviously.

He unwraps the candy and puts it in his mouth, then rubs his fingers over the plastic wrapping, feeling rather than hearing it crinkle between his fingers.

"...Try that." He holds the wrapper out to the Medicine Seller.