Nevertheless, it is possible to empty the tank by removing the powder in a plastic bag (the most tightly as possible to prevent the powder from escaping). Then rinse the tank with clean water (flushing your toilet because it's very messy). Finally just let the tank dry and then place it back in the printer. If the printer still say you change the tank is that it is not clean enough and the sensor is still clogged. This is the middle of the tank (at the letter C), just below a small piece of foam.