The American Society for Testing and Materials (ASTM) presents six groups of contaminations in their manual "Choosing a cleaning process" and relates them to the most common cleaning methods, thereby the suitability of cleaning methods for the removal of a given contaminate is discussed in detail. In addition they list exemplary cleaning processes for different typical applications. Since one has to consider very many different aspects when choosing a process, this can only serve as a first orientation. The groups of contaminants are stated as follows: