Polyester fiberfill is a blend of polyester fibers that crafters often use as filling material for stuffed animals and home decor projects, according to Fairfield, a fiberfill manufacturer. Fiberfill also is used as insulation in jackets and comforters.
The stuffing material is usually available in white or light colors, which keeps the filling from showing through the exterior fabric. Fiberfill that is treated with silicone is soft and flexible, much like down filling. Fiberfill that is untreated has a more coarse texture that packs tightly into items that need to retain a firm shape. The material comes in a bulk package and is easily separated by hand.