Turn the pot on its side in early to mid fall after the plants finish flowering and the foliage begins to yellow. Pull the soil and bulbs from the pot gently so you don't damage the bulbs.
Rinse out the pots with water. Scrub any white fertilizer salt buildup from the inside of the pot rims with a nylon or wire brush.
Fill the pot 2/3 full with moist potting soil. Use the same type or quality of soil that the lilies were growing in previously.
Wash the soil from the bulbs with clear water. Twist the small bulbs off the larger main bulbs.
Place the bulbs back into the pot, leaving approximately 6 inches between bulbs. Add soil to the pot until the bulbs are planted approximately 4 inches deep. Plant the new bulbs in new pots or plant them into a well-drained, sunny garden bed, as desired.