Use one part caustic soda for every four parts of water. Useful tips to make your everyday life just a bit better. The machine can also be used for high pressure cleaning of driveway, footpaths and brick work. If you have blocked drains, why not call jim’s plumbing we are able to clear blocked drains. Boilers and pressure vessels that may be. The £50 callout excess does not apply to new boilers in warranty only other items you have on cover external.