If you have big enough lingerie bag for protection and drop it in the washing machine. Otherwise, double check your washer to ensure there is nothing in it that will snag the yarn. Wash alone. It may require an additional spin cycle to get out the extra water.
Add a dash of mild detergent to the washing machine and turn it on, selecting either the delicate or or hand-wash cycle
Lay out a tarp or shower curtain in a safe place, and then place a clean white sheet on top of it. Reshape the blanket and lay it flat on the sheet to dry for 24 hours.
Fill your bathtub or a large basin with cool water. Add a pinch of mild detergent and agitate the water to create suds.
Place the blanket in the water and swish it gently back and forth to work the suds into the fibers. Let the blanket soak for 15 minutes.
Drain the tub and refill it. Gently swish the clear water through the blanket. Drain, refill and repeat until the suds are gone. Press out as much of the excess water as you can by squeezing the blanket without wringing it.
Carefully lift the blanket from the tub and wrap it in clean, white bath towels. Roll the blanket in the towels, and squeeze to remove more water. Do not wring the blanket.
Spread a plastic sheet or shower curtain on the floor where no one will disturb it. Carefully lay the blanket over the plastic sheet, smoothing it into its original shape. Leave the blanket to dry for 24 hours. If the blanket is still damp, place a fresh sheet under it. You can speed the drying process by running a fan near the blanket.