You'll know the ink pad needs re-inked when the impression starts to look light. Turn the stamp to the back. Push the stamp down slightly. Using your thumb and index finger, pull the pad out. Flip the pad over and add 5-10 drops of ink to the pad. Once the ink has absorbed, flip the pad back over so the inked side is down, press down on the stamp slightly, and insert the pad back in to the stamp. Please ONLY use a water-based ink.