The yarn should be hand washed in lukewarm water with a mild detergent, then press it out and dry it hanging on a rope. The dry yarn still needs to be “evaporated””, to remove any remaining creases and restore its fluffiness. To do this, place a colander in a pot of boiling water (however, it must not be submerged in water) and put the yarn in it. When all the threads are straightened, you can take the yarn out and hang it up, let it dry.