Abstract: A load cell weighs an unknown quantity of used bank notes. A micro-processor receives a signal representative of the weight of the notes and processes the weight representative signals to obtain an output signal representing the value of the notes weighed, or generates a warning signal indicating that a reliable value of the notes cannot be derived. The note value or warning is given by a visual display panel. The processing means obtains the output by dividing the total weight of the used notes by the average unit weight of a used note, and comparing the quotient from that division with the nearest whole number to determine whether the quotient differs from the nearest whole number by .+-.0.35. If the quotient differs from the nearest whole number by less than the .+-.0.35, the micro-processor multiplies the nearest whole number by the unit value of a note to give the money value of the notes weighed. If the quotient differs from the said nearest whole number by more than .+-.0.