Beth:
For shadow areas on flesh, I usually prefer a warm tone.
Per your question, I don't do pastels, but I believe the concept is the same for both oils and pastels. Neutralizing colors can be done in two ways - the CA way of blending the color with its opposite on the color wheel, or the CV way of blending the color with a gray of the same chromatic value as the color. Again, I don't work in pastels, so I don't know how well this might work as you would apply one to the other and blend them together.
Jean: I just wanted you to be cautious. There are many ways of painting.
