Mechanical decontamination is the opposite of chemical decontamination. Whereas chemical decontamination removes contamination from a surface without any physical interaction, mechanical decontamination doesn’t require any chemicals and relies solely on physical interaction.
Claying is a prime example of mechanical decontamination. During claying, the clay-material scrubs the surface clean by “grabbing” the unwanted particles, and pulling them away from the surface. The clay is slightly abrasive, which affects the surface slightly. The use of a claylube should help to move the clay over the surface and to minimize the amount of marring that is being created. Claylube usually doesn’t have any effect on the contamination itself. The polymer clay acts as the medium that removes the unwanted particles from the surface. This physical and mechanical interaction is a well known example mechanical decontamination.
Unlike chemical contamination, it is easier to determine which part of the surface is decontaminated, and which surface is left alone. In many cases the medium that is being used for the decontamination process can be cleaned and reused, the chemical that might be used for chemical decontamination is very rarely re-usable. Making mechanical decontamination often the cheaper option in the long run.
Another case might be that mechanical contamination hardly differentiate between different types of contamination. Meaning that clay will just remove anything from the surface, regardless of the type of contamination. Chemical decontamination can be made in such a way that the chemical only attacks a certain type of particles.