the question is not straightforward to answer, because there is no such thing as a worst location but a number of sampling points considered worst cases. The criteria to select sampling points are not the same for active ingredients, for microbiological sampling and for cleaning agent sampling. As a general rule, for soluble actives, micro and cleaning agent sampling, the points are located in the lower part of the equipment, because it is the last to rinse and last to dry portion, potentially concentrating solubles and fostering microorganism growth. For insoluble analytes the points are spread over the equipment including the hardest to clean and inspect locations, the locations with most intensive product contact, and “worst case” points representative for the big surfaces of the equipment. A good starting point for manual cleaning is the experience of the personnel responsible for the cleaning. For the V-blender the choice should include the walls (upper, mid a lower parts), the lids including gaskets, and the discharge valve including the bushings. For the capsule filling machine there are too many types to generically define sampling points. There should be at least five sampling points in very simple pieces of equipment, being ten samping points a good average but depending on equipment complexity. The number of swabs for each sampling point, and the sampling solvent should be determined during recovery studies, but more than two swabs for each sampling point may indicate a weak sampling procedure or a inadequate sampling solvent. The selection criteria for the sampling solvent include solubility of the analyte (high), volatility (medium), toxicity (low) and flammability (low).