To clean pipelines, you require a ‘Pipeline Inspection Gauge’ or pig. These come in a variety of forms, each with its own application. They are predominantly manufactured in specially formulated Polyurethane but in case this is not compatible with a line medium, special materials can be offered. They are generally categorised as follows; Spheres (solid or inflatable), Foam pigs (PU-coated or bare, in various densities), Cup-type pigs (uni-directional, manufactured from Polyurethane), Bi-Directional (bi-directional, manufactured from Polyurethane). Recovery efficiency will also increase in the same order. Therefore, a Bi-Di will remove much more from the line than a sphere.