Cellulose sponges are made from a mixture of regenerated wood pulp and cotton that are mixed together, treated with chemicals, heated and extruded into shape.
Melamine sponges are made from carbon, nitrogen and hydrogen. A German scientist,Justus von Liebig, created the material in the 1830's. Melamine is used for sponges that can eliminate crayon and other tough stains from walls.
Natural sea sponges are living animals in the phylum Porifera. These are the least desirable option for kitchen sponges because the animals have been over-harvested The loss of sponges negatively affects other creatures such as the hermit crab as well as those animals dependent on this crab species.
Loofah or luffa (Luffa aegyptiaca) sponges are the mature fruits of the luffa gourd. The ripe fruits are a mass of fiber cellulose that can be used for kitchen sponges, cleaning around the house and for bath sponges. Luffa is grown in tropical Asia and Africa but can be imported to grow outside of these regions. The luffa gourds, are dried and peeled to reveal the inner cellulose and rinsed in hydrogen peroxide or weak bleach to lighten the color.