A Dying Breed

The profession of  'chimney sweeps' fortunately is slowly dying out, due to heating being achieved more and more by electric power, gas and oil and less and less by coal.
In the 17th, 18th and 19th Century the Chimney Sweep was a most needed and respected profession.
A master sweeper would engage a number of young boys, some as young as 6 years of age, since 4 & 5 year olds were not strong enough for this grueling task. The boys were taught to climb up chimney stacks, by using their back and knees to wedge themselves up a soot-laden chimney.
If you read the history of these children you will find it hard to believe how they were mistreated:
They were either obtained from a "home for parentless youth", or purchased from their parents for about 7 shillings. They were then trained to climb chimneys and by wearing a hat with stiff bristles, and by wire brushes in their hands it was their task to loosen the soot from the walls of the chimneys. After having cleaned 4 to 6 chimneys they would be taken to the Masters home where they slept in the basement. 
They were given sufficient water to wash themselves,  at the best of times once a week and in some cases only 3 times a year:
At Christmas, Easter and one other religious holiday.
The cruelty with which these children were kept almost as slaves and prisoners is today incomprehensible.
For their labours they received no pay, but were fed by their masters.
When they had suffered an injury or grown too big to climb inside these chimneys, they were simply put upon the street, or sent back to their parents.

Today, sweeping is a rare and dying profession and 'sweeping boys' are of course no longer used.

Two Chimney Sweeps ( one a young woman ) in Vienna.

Today, the actual sweeping is accomplished by motorized brushes from above.

Source: Wikepedia.