Processes using enzymes or micro-organisms in order to: liberate, separate or purify a pre-existing compound or composition, or to treat textiles or clean solid surfaces of materials are further classified in subclass . This group does not cover: chemical or physico-chemical type processes where eradicating or diminishing the dangerousness of harmful chemical substances produces useful products (e.g. cement). These types of processes are covered by the appropriate subclass for making the specific product. However, in situations where processes for making products include a subset of process steps with eradicating or diminishing the dangerousness of a harmful chemical substance as its fundamental goal, and this subset is in itself novel and unobvious, this subset is covered by group . In this group the following term is used with the meaning indicated: “harmful chemical substances” are chemical waste substances which are too hazardous or toxic to be discarded in an ordinary municipal landfill. In this group, at each hierarchical level, in the absence of an indication to the contrary, classification is made in the first appropriate place. In this group, it is desirable to add the indexing code(s) of group relating to the nature of the harmful chemical substance. When indexing a substance in groups - , indexing according to its chemical structure may also be made in one or more of groups - .