I had a horse whom I thought was the world’s dirtiest horse. Although he was extremely neat about his stall, when it came to his body, he loved to me caked from head to toe in crusted mud. Sometimes only his eyes would be mud free. I did blanket he m as early as possible but in the spring I would sometimes walk into the barm and people would ask if I was there to ride. When I said yes, they would laugh and say they were so sorry because they had seen him in his paddock wearing a lovely mud crust. Did I mention he was grey? I found two answers. 1) a warm bath and heat lamps. 2) a vacuum. Both worked extremely well. Good luck!