Basically due to their chemical resistance components made of plastics are widely used in pickling, activation/passivation and coating processes. Thus, operational and occupational safety in surface technology depends on the proper selection of these materials. Despite the use of aggressive media-partially at elevated temperatures-little is known about the long-term durability of plastics in these processes. Resistance lists give only inadequate information about the actual behavior under operating conditions, because often the chemical attack of components is intensified by mechanical stress, such as abrasion, shock load, vibrations or cavitation in pumps and pipes. Last but not least, the characteristics of the respective plastics depend also on their processing conditions. The following article should help to raise awareness among metal finishing plants for the dangers emanating from the lack of resistance of synthetic materials.