Green gritty stuff from rocks and volcanic ash stimulate nerves under the skin and, being somewhat abrasive, rubs off dead skin cells. Dry the mud with a sun bath, then shower it off in a mineral shower and a mineral bath. Next: a hot pool with water at 40C/104F opens pores, allowing the minerals to seep in. Finish in a cool pool. It did feel good. However, mud collected in my swim suit managed to escape all this rinsing. Finally back at the hotel, rinsing the suit six times finally yielded water that wasn't green.