It is not a good idea, either, to attach material such as Krystal Flash or Flashabou, then trim all strands at one spot. This gives most of the reflectiveness at one location - where the strands were severed. Instead, clip off the strands at different lengths along the entire body - that way you'll see little sparkles of light throughout the pattern

Advanced Fly Fishing Techniques: Secrets of an Avid Fisherman (ed. Delacorte Press, 1992)