Dig out the daffodil bulb as soon as the top foliage has withered away. Work a spade in a downward angle around the base of the plant to loosen the soil. Dig several inches from the plant's withered base to avoid scratching or breaking the underground bulb. Reach in and lift the bulb out of the ground.
Brush the bulb to get as much of the soil off as possible. If mud or clay are encrusted, spray the bulb with water to get it off.
Place the bulbs in shallow plastic trays, according to the University of Missouri. Alternatively, the university suggests putting them in fabric onion sacks or inside old nylon stockings.
Cure the bulbs. Put them in a dark, well-ventilated room that has an average temperature of 60 to 70 degrees Fahrenheit, according to the University of Minnesota. Store them there for approximately three weeks to allow them to properly dry, and then pack them away in a cardboard box.