Do you actually hand wash your delicates or do you abuse them by laundering them on the heavy cycle with your jeans?
If you are advised to hand-wash your sleepwear, use a gentle detergent made especially for delicates, such as Woolite.
Satin lingerie is easy to care for, but like most delicates, it requires gentle washing for the longest life.
If you can launder your pajamas at home, use cool water and a detergent made for delicates, such as Woolite.
To get the longest life out of these socks, wash them as you would any delicates; either hand wash them or place them in a lingerie bag before putting into a washing machine on the gentle cycle.