High pressure water jets are good, but if you do not have the equipment, a large quantity of very hot water will do as well. This will melt the deposits and flush them down the pipe. I flush my home's kitchen and lavatory drains once a year with a large stewpot full of scalding hot water. This must be done with great care by someone strong enough to keep the pot under control. Wear a long sleeves and pants and a raincoat over to protect from splashes, use heavy mits and pour slowly. Take steps to make sure no children or pets can come near. Make sure your path is completely clear. Failure to take great care can result in a very bad burn. Done regularly, this maintenance can greatly reduce, or even eliminate, blocked waste pipes.

The most effective way to clear the drainage pipes and inspection chambers of these deposits is high pressure water jetting. The high-pressure water spray acts like a sharp knife and cuts the grease off the walls of the pipe. The water used in the process itself creates a high water flow which will flush the sediments down the line.