If You Care Sponge Cloths are made in a patented process from a three dimensional blending of cellulose, non-GMO unbleached cotton and mirabilite – a natural mineral salt. During the production process, the mirabilite is washed out, leaving the remaining blend (70% cellulose & 30% cotton) extremely porous, which makes the sponge cloth extraordinarily absorbent. It can absorb up to 20 times its own weight in water.