Cotton and silk are durable and breathable, silk being especially lustrous and lightweight with natural temperature regulating properties. Refer to manufacturer's care instructions for a machine washable option. Wash socks inside-out to keep a pristine outer appearance on a low temperature. Add a little fabric softener to recondition the yarns, adding softness and a little more stretch. Do not tumble dry. When hand-washing use a low temperature and rinse in clear water.