This document provides instructions for writing invisible messages using simple materials like paper and pencil without special ink. The method involves writing a message with pencil on one piece of wet paper, placing a dry paper on top, and peeling them apart to reveal the message imprinted on the wet paper. Once dry, the message disappears, but can be viewed again by dipping the paper in water and holding it up to light. An alternative method uses milk as the writing medium, which also renders the message invisible until heat is applied.