The rayon that was once soft and drapeable may become stiff and harsh. And, it's important that these directions are followed. The constant agitation of the washer, and tumbling of the dryer will eventually cause the fiber to break down, and will shorten the life of the garment. Typically, silk comes from the cocoon of a silkworm, which feeds only on mulberry leaves. A diet of mulberry leaves produces the finest, silkiest fiber.
Wild silk comes silkworms which feed on a variety of leaves, including oak and cherry trees.
Wild silk is often brown or somewhat nonuniform in color, thicker, and less lustrous. When cool, there is no discernable smell. Regarding your smelly silk, it is probably the dyestuff chemicals used in the dyeing and finishing processes that is causing the odor. Inc. Spandex is a lightweight durable fiber, most often blended with nylon and used in such garments as bathing suits, bodywear, and panty hose. It is more flexible than conventional elastic threads, and has two to three times more restraining power.