verb - to force a device called a pig through a pipeline or a flow line for the purpose of cleaning the interior walls of
the pipe, separating different products, or displacing fluids
Pig: a scraping tool that is forced through a pipeline or flow line to clean out accumulations of wax, scale, and debris from
walls of the pipe. It travels with the flow of the product in the line, cleaning the pipe walls by means of blades or brushes
affixed to it.