Gold Plus Group supplies Heat Soaked Glass [Gold Plus - Heat Soaked Glass]. Gold Plus Group is an ISO 9001:2000 certified companies. Gold Tuff Toughened Safety Glass and Heat Strengthened Glass can be specified Heat Soaked. Heat Soaking is a quality control check carried out, when specified, to detect and reject any Toughened Glass that may have inclusions [Nickel Sulphide] or edge defects that may cause breakage after installation.