I use one of my coolers. Take apart my MR pack. Fill the cooler with cold water, put some Dawn in the water. if I have really heavy blood I will put some dawn on the pack and scrub with a soft brush. Let it soak overnight in the cooler. Heavy rinse with garden hose next morning. All blood stains are gone.
I use the car wash, what I trust over time and with kids and family using bath it is tough to justify that and possibly forgetting to clean that afterwards lol.