Method for imparting stain resistance to fibers, especially wool, which is adaptable to current wool processing methods. Steps comprise:
A. treating fibers with a mordant;
B. treatment with a combination of sulfonated or disulphonated surfactant together with a stain resist (e.g., syntan); and
C. providing treatment with a fluorochemical in either step A. or B. in an amount sufficient to improve stain resistant properties. The improved method may be undertaken in the liquor remaining in a dye bath after dyeing fiber (spent bath process). Process pH is acid. Advantage: lowers the proportion of stain resist chemical to wool necessary to impart stain resistance. Tip sealing, using polymethacrylic resin and fluorochemical, may be an added step.