Hand wash in cold water with a gentle detergent like a wool wash or Dawn dish soap, submerge in clean water to rinse (if not using a rinse-free wool wash), roll in a towel to squeeze out water, and lay flat to dry.
Superwash yarns may be machine washed in cold water on delicate cycle and laid flat to dry, but we always recommend hand-washing to maximize the life of your finished piece.
While we do our best to avoid it, with any hand-dyed yarn your project may bleed a small amount of dye when washed. This shouldn't affect the finished color of your project. If there's more than a faint tint of color in the wash water, a few tablespoons of vinegar in the rinse water should help (the smell will dissipate once dry).