Too funny this, a dried loofah plant. The loofah is a one-year climbing plant from the cucumber family. The young fruits can be eaten like a cucumber. If you let the fruits dry, they turn into a sponge. When the sponge is wet it swells slightly to become spongy and flexible. I use the sponge myself to clean the sink with green soap. Sands well when the sponge is dry.
A great alternative to plastic scourers.