No, women do not have a self-cleaning mechanism of their genitals. The genitals, like other parts of the body and more so, need to be kept clean by frequently washing the area with running water. However, it is not necessary to use soap in the area since soap is alkaline and there are greater chances of harbouring infections in an alkaline medium than in an acidic one.One thing is very clear though. There is no doubt whatsoever, that genitals should be washed with water as often as possible. Also wear clean, cotton underwear which should be changed at least once everyday. More hygiene needs to be maintained when the girl is menstruating. Hope this clears your confusion.