To wash (or scour) an extremely dirty wool fleece, place the fleece in the bathtub or a washtub or other large container and cover it with cool or room temperature water. If the fleece is matted, it should be picked before washing. Grease and dirt will be retained in dense clumps of fleece. After soaking for at least twenty minutes, squeeze out the water and place the fleece in an automatic washer. This pre-soaking removes the worst bulk of mud and sludge and keeps it out of your washer.
Wash: Fill the washer with water too hot for your hands and add detergent (2 or 3 times what you would use for a load of laundry). Use only your favorite detergent. Orvus is fine or Arm and Hammer, Tide etc. Do NOT use fabric softener or other additives. They leave a residue which interferes with carding. Turn off the machine.
Do NOT allow wool to agitate! Agitation of wool in hot water will cause it to felt! This is irreversible! Allow the fleece to soak for about 20 minutes. Next, move the dial ahead to the drain and spin cycle and spin dry it.
Rinse: Add hot clean rinse water using a piece of wood to deflect the water as it fills. Soak for another 5 minutes and spin dry again. Repeat until the rinse water is clear.
Dry: Spread the fleece to dry on an old screen door laid across two saw horses. A fan to move air through the fiber will speed the process.
Test: When the fleece is thoroughly dry, test for tackiness by rubbing a small lock between your thumb and forefinger. If you feel any residue on your fingers, repeat the washing process.