The bristles may be nylon or fiber, or some may be a combination of nylon and steel bristles. The bristles on the sweeper should be checked to ensure they are in good condition. The width of the brush should be checked for evenness. If the bristles are worn off unevenly, too much pressure will be exerted in one spot and the bristles may not make contact in another. If there is a visible unevenness, the bristle assembly should be replaced.