Laboratory techniques are described for the identification and characterization of polyester, nylon, and acrylic fibers when blended with wool. Polyester tests include molecular weight, separation from wool blends, critical dissolution time and dye affinity. Tests for acrylic fibers include microscopic identification, solvent-extractable matter, dye affinity, and shrinkage potential. Nylon fiber tests include identification of three types of nylon, quantitative analysis of wool blends, dye affinity, oxidative degradation, viscosity, and hydrolytic damage. -- AATA