Friction and cleaning: especially spices like thyme, savory or marjoram undergo this process. During this process the material is separated into several cuts and each is cleaned separately on sieves and in zig-zag air classifiers. Consequently, we can thoroughly clean the material to reach very low AIA levels and remove other unwanted materials (stems, earth lumps, stones, glass and plastic). An installed metal detector allows for identifying ferromagnetic and non-magnetic material as well as stainless steel.