Hat done, washed, and blocked. Not photographed yet, but hey at least I've gotten this far.
Washed in hot water, yes, HOT, with Soak no rinse wool wash, and a splash of white vinegar. I let it sit for at least an hour or more, depending upon when I remember to pull it out of the water.
Gently squeeze the water out, smoosh in a towel to remove more water and stick it on a clean towel on the radiator to dry.