Hydroblasting

Hydro blasting is a type of cleaning method that makes use of the force of water to achieve a clean surface on the material in question. Unlike other types of cleaning processes that are related, toxic and potentially hazardous abrasive chemicals are not used to strip off a surface. Instead, water is channeled through a pressurized system to blast the target material in a highly focused and pressurized beam.
To distinguish hydro blasting from a procedure of simply washing a surface off with water, professionals will classify the washer according to the pressure of the stream of water that it emits. Generally, water jet systems that emit water at a pressure greater than 700 bar are considered to be hydro blasters. Anything less than that will generally be considered to be either a low pressure or a high pressure water washing system.

Needless to say that this work is dirty, heavy and dangerous. Dirty and heavy is obvious, only take a look at this picture. And dangerous because these blasters will strip all your flesh from your bones within a split second if you point the nozzle towards human parts. And all that for a poor payment.