Just clean it up. Wear gloves and a mask to prevent anything getting in your body. Just be careful about what cleaning products you use to prevent releasing dangerous gasses and do it in a ventilated room or outside. But I would recommend that for any battery or strong acid or base or other reactive chemicals, not just lead containing ones.
Yeah good message, but permanently ruining something that benefits society is not the way. Spray painting a wall is fine, but a book is not. You’re just doing the job of fascists for then when you destroy knowledge.