Cut open the ripe peppers and remove the seeds. Try to separate the seeds as much as possible from the flesh. We recommend wearing (latex) gloves to avoid getting the sharp capsaicin on your hands.
Place the removed seeds on a plate or a piece of cardboard. Do not use a paper towel as the seeds can stick to it and may get damaged when removed. Let them dry for 2 weeks in a well-ventilated place, away from direct sunlight.