After I purchase the wool I scour it. This really means that I let it soak. Usually I rinse and soak several times to get most of the dirt and poo and pasture particles out of it. If I agitate the wool too much, it will felt. If I decide to dye the wool, I like to use the rainbow dye method. Below is a modified version of rainbow dying which I did last week.
I started by filling a large stainless steel pot with water. The water should be prepared according to the dye manufacture directions which usually means that I should add salt or vinegar to the water. Place from one to two pounds of wool into the pot. The wool should also be wet when placed into the dye pot. I made a big M across the top of the wool with fluorescent green color dye. Then I used a pine green dye across the top and the bottom of the wool in the pot. In the center of this M, I placed cantaloupe melon color dye. In the center of each of the M arch, I placed yellow dye. I let this mixture sit for a while and then I may flip the wool over and get all of the dye mixed in. Normally I can skip this step, but I used a new fluorescent dye for the M and it needed some aid in order to penetrate into the wool. If the wool is too tight together, natural wool color spots will show. (This may be a desired affect). If I get a little heavy handed with the dye and I use too much, I will place more wool on the top of the dye so sop up the excess. I weight it down with a plate and a jar of water on top of the plate. Once I get the water and wool to a boil, I turn off the heat, place a lid on the pan, and leave the dying wool over night. The next morning I rinse the excess dye out of the wool and lay the wool out to dry.