Wow. Just reading about washing horse blankets tired me out! Both replies were interesting because I don’t blanket my horses as a rule, and I had no idea there was so much involved, especially with waterproof blankets. OP, let me ask you some questions. No need to answer, I’m just thinking out loud. Is your horse indoors or outdoors? Do you show? And where do you live? The only blankets I’ve ever put on a horse are fly sheets, because my mare is allergic to fly bites, and I hand-wash mine in a big sink at the barn using horse shampoo. What I’m getting at, is there a reason why your horse needs blankets?