Naftalan's petroleum spas were immensely popular in the 70's and 80's until ethnic war with Armenians in nearby Nagorno-Karabakh broke out. The Azerbaijani town of Naftalan, 160 miles north-west of the capital Baku, there is a clinic where visitors voluntarily flock to its famous (well, famous at least in the former Soviet Union) clinics to bathe in crude oil. The practice has supposedly been around for centuries and is believed to treat scores of illnesses, including arthritis, rheumatism and psoriasis.Azerbaijan is an oil-rich country, but the crude found around Naftalan is too heavy to be usable in industrial applications or to be exported, so it is designated for 'medicinal' use instead. A 15-day, $450 treatment basically consists of the patient sitting in a tub of crude for about 10 minutes before being wiped down by an attendant with paper towels, followed by a series of showers.
Patients lower their bodies into 35 gallons of crude oil, at a temperature of 40 degrees. Many of them say the warm oil relaxes their joints and they'd love to spend more than 10 minutes soaked in black oil, but since it contains almost 50% naphthalene, a hydrocarbon deemed potentially carcinogenic by EU regulations, longer sessions could be hazardous to their health. The clinic's doctors claim millions of people have been treated at Naftalan over the years, and none of them have suffered any complications, as a result. Still, to be on the safe side they limit the sessions to 10 minutes, and no more than a bath per day, during a 10-day treatment.