Cable machines have their place, but jets are the best bet for clearing grease, sand and even ice from drain lines.
Nothing clears the line faster than a jet. When a drain-cleaning cable goes through grease, the grease will close up behind the cable and still leave the line clogged. A jet, however, use a stream of high-pressure water that hits the stoppage and flushes it away. The thrust of the nozzle drives the hose down the line and gives you wall-to-wall cleaning action. If you are in a cold climate, jets can be used to clear lines clogged with ice. The larger gas jets can clear a foot of ice per minute in a 4-inch line.
"We use a camera system after the line has been jetted and the drain pipes look as good as new," says Bob Garbutt of Pipeline Mechanical. "You can actually read the writing on the walls of the pipe."