Now myself 66 years old, I am investigating my father's methods, after a long period of neglect.
These three dyed yarns were acquired recently. I separate them into three or four separate strands.

Next I pull the fibers out from the stands, and mix them in the coffee grinder.

Then I cut them into smaller pieces for spinning on the Clark spinning block.

Here's a fly with one of those spun bodies in the thorax, and a wool dyed salmon pink for the abdomen.
Embroidery wool is available in an amazing variety of colors.
This fly has too much hackle, a perennial problem with my tying technique.

Hook: 14 Mustad R50-94840
Silk: Light orange
Hackle: Light rusty dun hen
Body: wool yarn dyed salmon pink
Thorax: spun body with gray, yellow and red yarns.
Lance