How To Wash Viscose Without Shrinking | The Laundress
Viscose is a type of rayon. Although many rayons CAN be washed, viscose has been known to shrink to extreme proportions. Unless the garment is specifically marked washable, DO NOT wash it.
We also find that rayon and viscose are often not labeled properly, and we do not recommend taking the risk of washing it as the shrinkage, elongation, distortion, or puckering is not reversible.
Example: Our often-cited "why not to wash viscose" example is the classic black matte jersey wrap dress by Diane Von Furstenberg. It shrinks to half its size!
Polyurethane is sometimes blended with viscose or rayon. We don't recommend washing items that contain polyurethane since this fabric can expand when laundered. (Examples include women's blazers and suit pants, often from Italian brands.)