No tracing or copying was used. Based on research. With this method of filtration, a openwork metal disc was placed in an asbestos sack. The sack would then be loosely gathered and tied around the disc, and then another disc placed inside the sack, tied off, and so on. When the sack was filled with discs, the end of the sack would be attached to a hose. A pump would suck the wine through the asbestos sack into the wine barrel.