The paper reports on the pollution performance of different insulators and surge arresters at Glogow test station from 1981 up to 2004. The environmental protection progress and technology modernization caused a significant decrease of dust and gas emission at a nearby copper smelting plant. As a result, the pollution severity of the area changed from pollution level IV (very heavy) in 1980s to pollution level I (light) after 2000. The flashover voltage was measured on porcelain post insulators under natural conditions in 1987 and, after insulator wetting with a water spray, in 2002-2004. The electrical strength of porcelain insulators was compared with insulators coated with a silicone rubber layer and with insulators coated by fluorourethane layer StaClean. The aging of insulator glazes and corrosion flanges are described. The external and internal charge records and temperature on metal oxide surge arresters with porcelain housing are also presented.