How should the tar bar soap be stored correctly so that it does not soften and lasts longer? — DD TAR SOAP FOR FACE AND BODY 70G - ELFA (degtjarnoe)( дектярное)

The card does not describe the rules for storing the soap: it says to see the packaging and to keep it out of the reach of children. The shelf life is also on the packaging.

General information (not a manufacturer's instruction): bar soap is usually better kept on a dish with drainage, so that it does not stand in water.