What is the difference between the Rapid Method and Patented Leach Method in lead testing?

Use the Rapid Method to quickly test for surface lead on painted surfaces, dishes, fine china, pottery, ceramic ware, mini-blinds, circuit boards, toys, bathtub glazes, antiques, food can seams, plumbing fixtures, solder, lead foil, and ceramic tile. Use the Patented Leach Method for the sensitive testing of multi-layered or dark colored paint/paint chips, soil, dust samples, dishes, pottery, ceramic ware, fine china, jewelry, candle wicks, and any other materials.