Feed lines. Whether feeding the machine from the drying hopper, gaylord, orbag, it is critical to ensure that all of the material has been cleaned out. This isusually as simple as removing the feed line and allowing the vacuum loader tosuck all of the material out of the feed lines. There have been cases were thematerial handler does a nice job of cleaning everything out but forgot the feedlines and when the new material was introduced all of the previous material waspulled in with it, contaminating the material.