Remember to remove the impurities accumulated on the surface of the skin (sweat, sebum, dead cells, dust, cosmetics...)
Water alone cannot eliminate all the impurities and pollution of daily life. To be effective, it must be combined with what are called "tensio-active" substances, which have the property of "wetting the skin" and enveloping the dirt.
Real soap is too detergent because it eliminates the hydrolipidic surface film, the skin's essential shield against external aggression, and its alkaline pH unbalances the skin flora.
It is thus necessary to choose effective hygiene products but preferably without soap, with surface-active agents selected for their extreme softness.