Wool and other animal protein fibers have quite a lot of variation between species, individuals, breeds, genetics and even environment. Because of this, it would be unrealistic to give one certain set of directions for use. The most valuable tool an individual can have is basic understanding of the specific fiber they’re washing as well as experience. Fibers with more oil and dirt need more shampoo, fibers with less oil and dirt, need far less.
“Wash and Dye Bastard was designed to condition fiber and boost dye uptake. Dirty Rotten Bastard was designed to scour fibers and as a prewash for oily fibers before using Wash and Dye Bastard.”
Both products were formulated to be used (quite literally) as shampoo; wet the fiber before application with medium-hot water, squeeze out excess water, then gently massage the product into the fiber. Leave the shampoo on for 5 to 15 minutes (an expandable colander over the sink works well), then rinse in medium-hot water. Repeat if necessary. What would make repeating necessary? A greasy feel, or visible dirt in the rinse water. Wash and Dye Bastard used this way deeply penetrates the fiber cuticle, significantly increasing the dye uptake. Prewashing (using the same process) with Dirty Rotten Bastard will give added scouring benefits to oily fibers. As with any fiber washing, do not change temperatures or handle the fibers in an aggressive fashion; this can lead to substantial felting and over processing.