We performed applied functional tests to examine how the noncrosslinked fraction of a cured silicone elastomer affected the performance of electrical devices and the solderability and adhesion on gold-plated printed circuit boards. To obtain information about the spreading tendencies of commercial silicone elastomers, and to complement the function tests, we conducted so-called creep tests to examine the migration and spreading of the noncrosslinked fraction. The electrical tests, performed with both reference oligomers and cured commercial poly(dimethyl siloxane)s, showed that failure occurred even at very low silicone contamination levels. The solderability and adhesion, however, were not affected by the presence of poly(dimethyl siloxane)s, especially not the reference solutions, which consisted mainly of volatile siloxanes. The creep tests, performed on commercial silicone elastomers, indicated that the noncrosslinked, nonvolatile part had to be taken into account in a discussion of silicone contamination. (C) 2003 Wiley Periodicals, Inc.