These Sferra Catena pillowcases are easy to use. Just put them on your king - size pillows for a touch of luxury. When it's time to clean them, use a gentle cycle in warm water. Don't use bleach as it can weaken the fabric and make it yellow. Also, avoid fabric softeners. Wash dark - colored pillowcases separately. Tumble dry on low heat and take them out while they're still a bit damp. You can steam iron them on the 'cotton' setting, but do it on the reverse side of the fabric.