there is disclosed a method of operating an injection - molding machine to produce a composite item that includes a portion of soft material such as a set of bristles tending to cling to a mold cavity in which it is formed . at a first station , a relatively flexible plastic material is injected into a first cavity shaped to define the portion of soft material of the composite item , that portion including a backing layer . the portion of soft material is then allowed to cool , and at a subsequent station there is injected a relatively rigid plastic material into a second cavity bounded by the backing layer . the second cavity defines a harder portion of the composite item such as a brush handle . after the latter portion has also cooled , the portion of soft material is separated from the first cavity by pulling on the harder portion at a rate of speed slow enough to avoid rupture of the portion of soft material .