Current methods of evaluating the amount and particle size of trash in ginned cotton are reviewed and the need for simplicity and speed in obtaining a measurement of trash content is evidenced. The authors discuss a new optical-electronic method of scanning a classer's sample to record both particle size and number of particles. The sum of the areas in the sample which are darker than the background is taken as a percent of the total area scanned. The method utilizes a closed circuit television camera, which in a fraction of a second traverses the face of a sample and reads out the desired information directly. Results of tests designed to prove the reliability and validity of the method are shown and a comparison to current methods of evaluation is given. Diagrams of the optical and computing systems used in the method are explained in detail.