plants like application of corrosion protection layers or phosphating. Cleaning can also be simple: the cleaning processes are integrated into other processes, as it is the case with electroplating or galvanising, where it usually serves as a pre-treatment step. The following procedure is quite common: Pre-cleaning Main cleaning Rinsing Rinsing with deionised water Rinsing with corrosion protection Drying Each of these steps may take place in its own bath, chamber, or, in case of spray cleaning, in its own zone (line or multi-chamber equipment). But often these steps may have a single chamber into which the respective media are pumped in (single chamber plant). Cleaning media plays an important role as it removes the contaminants from the substrate. For liquid media, the following cleaners can be used: aqueous agents, semi-aqueous agents (an emulsion of solvents and water), hydrocarbon-based solvents, and halogenated solvents. Usually, the latter are referred to as chlorinated agents, but brominated and fluorinated substances can be used. The traditionally used chlorinated agents, TCE and PCE, which are hazardous, are now only applied in airtight plants and the modern volume shift systems limit any emissions. In the group of hydrocarbon-based solvents, there are some newly developed agents like fatty acid esters made of natural fats and oils, modified alcohols and dibasic esters. Aqueous cleaners are mostly a combination of various substances like alkaline builders, surfactants, and sequestering agents. With ferrous metal cleaning, rust inhibitors are added into the aqueous cleaner to prevent flash rusting after washing. Their use is on the rise as their results have proven to be most times as good or better than hydrocarbon cleaners. The waste generated is less hazardous, which reduces disposal costs. Aqueous cleaners have advantages as regards to particle and polar contaminants and only require higher inputs of mechanical and thermal energy to be effective, whereas solvents more easily remove oils and greases but have health and environmental risks. In addition, most solvents are flammable, creates fire and explosion hazards. Nowadays, with proper industrial parts washer equipment, it is accepted that aqueous cleaners remove oil and grease as easily as solvents. Another approach is with solid cleaning media (blasting) which comprises the CO2 dry ice process: For tougher requirements, pellets are used while for more sensitive materials or components CO2 in form of snow is applied. One drawback is the high energy consumption required to make dry ice. Last but not least,