In the bathroom: Store your bar out of direct contact with water. Bars should dry completely between uses, so avoid keeping them in places where they can get splashed or dripped on, or where water could pool up. Recommended storage options include soap boxes or dishes, hanging mesh bags, or a shower rack that is out of water's reach.
While travelling: Store your bars in solid, airtight containers while travelling to help keep their form and avoid any product waste. After use, ensure your bars are fully dry before putting them back into your travel container.