Although thermodynamically stable mixtures of at least a hydrophilic -, a hydrophobic - and an amphiphilic component, i.e. microemulsions, gain an increasing interest in technical applications, their manifold use failed up to now. One reason is the poor transfer of the scientific results to application. In this contribution examples will be given where this transfer (almost) succeeded. It will be shown that the ultra-low interfacial tension in microemulsions can be used for the efficient degreasing of animal skins. Using microemulsions as reaction media it is found that the large specific internal interface leads to a drastic enhancement of epoxidation rates. In another application microemulsions are used for clean combustion in motors, like e.g. diesel engines. It is known for a long time that the presence of liquid water in the compressed, hot combustible air-fuel mixture reduces the emission of pollutants like soot and nitrogen oxides. Often water-fuel emulsions are injected. Emulsions are thermodynamically unstable and therefore tend to separate. Microemulsions, on the contrary, do not separate because they are thermodynamically stable. We made microemulsions of water and diesel and tested these in truck engines. Soot was reduced by more than 90 % in steady state operation and about 97 % in dynamic (i.e. accelerating) operation. Nitrogen oxides were 40 to 70 % lower compared to the reference diesel. In certain modes of operation fuel consumption was reduced. Explanations and implications of these favourable findings will be discussed.