how to use them. (2) Employees shall not wear clothing which has an accumulation of flammable material on it. (3) Rags, refuse, sweepings, and other waste shall be kept in covered containers, wet down with water, and disposed of at least once a day by burning in a safe location. (4) Matches, cigarette lighters, and other similar sources of ignition shall be prohibited in any room in which nitroce