The U.S. Army used the George A. Cowles and Company patent moth, water and mildewproofing process from 1869 until 1876 to treat over 1. 5 million yards of fabric, 150,000 enlistment men's uniforms, and 20, 000 tents. The New York City Metropolitan police and several New York City awning and tent manufacturers also applied this process. The U.S. Army showed the process to be effective in water and moth repellency and possibly for mildewproofing. Copper, zinc, mercury, and alum may be left on these fabrics causing false positives for tests such as dye mordant identification. Caution should be used in treating these items since conservation work may remove or alter compounds destroying historical evidence and possibly causing further damage to the object. Identification of Cowles's-treated garments is by sleeve lining markings or by dating of uniform styles within the range of Cowles's process use.