Konjac is a natural herb grown underground with a soft texture for gentle cleansing that will not scratch while washing away dirt and oil from skin. For all skin types to use with or without cleanser to gently cleanse, and buff away blockages & dead skin cells. Cotton string provides a way to hang and dry the sponge between uses. Cleaning: Rinse and very gently press out water. Air dry away from sunlight. Replace monthly. Biodegradable. White: Pure Konjac Black: Activated Charcoal, Konjac *Sponges are hermetically sealed in wet state so customer can feel sponge bounce *Sponges become hard when dried but softened again with water.