During the Industrial Revolution, children of Britain usually between ages four and eight were trained to sweep chimneys. Parents would sell boys to work in chimneys. Very little girls were employed to work. The smaller the child, the higher the price they could be sold for. This job was full of risk and the conditions were filthy. The children would develop sores and bruises on their knees and elbows from working in the chimneys. Public buildings and big mansions were the most dangerous.