A number of quality control measures are used to ensure cotton swabs are acceptable. The spindles must be checked to ensure they are straight and free of imperfections, such as stress cracks or other molding defects. The cotton used to coat the ends must be of specific purity, softness, and fibre length. The finished swabs must be free from lose adhesive and sharp edges, and the tips must be tightly wrapped. These measures are particularly critical for swabs designed for infant use. For swabs intended for other applications, other quality requirements may be more important. For example, swabs used for biological purposes must remain sterile until used. For some applications, lack of loose lint maybe imperative. The particular quality control requirements will vary with the application. Of course, each box of swabs must be weighed to make sure the correct number of swabs are packed in each box.