Washing clothes is a basic need in civilised societies and, in general, in all the parts of the world. In primitive periods—before running water, washing machines and detergents—it was necessary to go to wash clothes at the river bank or in a laundry room. Clothes were washed manually, by rubbing and sometimes striking them against a hard surface with
soap. The aim was to penetrate the mix of water and soap between the fibres of the fabric to pull out the dirt. The
slabs to wash the clothes were slabs of natural stone chosen to present a fine and relatively flat surface. The small rounded irregularities could help of friction in the washing process. • In some cases "artificial slabs" were made especially, in which the friction surface was wood, although the apparatus was still called "washing slab". • There were also "artificial slabs" made with an
undulated steel sheet. (These types of
washboards have been used as percussion instruments in jazz and blues bands). • The wash to the stone of cowboys trousers and similar clothes is a stone washing process that uses the friction of some parts of the clothes against a coarse stone (or similar). The aim is to achieve a change of appearance of the clothes, imitating natural wear. == As hunting traps ==