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.
My routine after the season with my exo k2:
- separate waist belt, shoulder straps, bag from frame, remove pouches. Anything that isn’t dirty I don’t bother with . IMO high pressure and frequent washing will shorten the life of the fabric and waterproofing
- set large tote inside bath tub (55gal hdx)
- fill tote with water and following mixture: 1/4 cup borax, 1/4 baking soda, 1/4 cup dead down wind detergent, and if it’s real bad 1/4 cup of oxyclean
- let soak for several hours initially (6-12hrs)
- run 1-3 to however many scrub and rinse cycles with water/soap changes as necessary
- hang dry outside in the sun
Most of the time I can get away with just 1-2 cycles of the dead down wind, which is really impressive stuff for what it is. Something in the enzymes that they put in it seems to get blood out easier than any other detergent I’ve tried. Side note, I would also never use a perfumed detergent on a hunting pack if it can be avoided.
For really deep and/or sun dried in blood I will pretreat by soaking in cold water and salt mixture and/or will place large globs of wet salt on the big stains allowing it to dry. Salt pulls the blood out easily with a little science.