Backed by a faraglione (rock tower) and stinking of rotten eggs, Vulcano's harbourside pool of thick, coffee-coloured sulphurous gloop isn't exactly a five-star beauty farm. But the warm (28°C) mud is considered an excellent treatment for rheumatic pains and skin diseases, and rolling around in it can be fun if you don't mind smelling funny for a few days. Keep the mud away from your eyes (as the sulphur is acidic and can damage the cornea) and hair.
Once you have had time to relax in the muddy water, get some soft clay from the bottom of the pool and apply it to your body and face. Wait for the clay mask to dry, wash it off in the pool, then run to the natural spa around the corner, where there are hot, bubbling springs in a small natural seawater pool.