Dirty

The second part of Sascha's Azerbaijan journey. 
He now reports on the mud volcanoes, located a lot closer to the nations's capital of Baku. 

Sascha:

"The mud volcanoes are not real hot springs but none the less worth a mention. A visit is very touristic because they are only 60 km from Baku.

The highway to Qobustan is quite straightforward, but finding the volcanoes is particularly difficult. On internet (or in the Trescher Guidebook for Azerbaijan) the GPS coordinates are mentioned. Otherwise you will be obliged to pay for a taxi driver or a guide to show you the mud volcanoes. It seems that the absence of indications is purposely to provide some income to local taxi's who are waiting at the entrance of the park. 
But without GPS data and local help it is impossible to find the volcanoes.

Most of the people just take some pictures and leave the volcanoes after 10 minutes. As the mud has positive effects for the skin and the body, you should nevertheless benefit from a unique experience and take a soak. 
Take pictures before soaking, after the soak you are too dirty. 
 
The mud is not hot, but neither cold; I would estimate about 25°C. 
Due to the high mineralization, there is a floating effect similar to the Dead Sea.

 

From the volcano, you can see a small round lake with the possibility to clean yourself. 
Another smaller lake with cleaner water can be found further down the hill. Anyhow, I did not get 100% clean; so it is advisable to wear old clothes and protect the car seats and bring a towel with you that you do not need anymore".

Bubbly
More info gleamed from our never-ending source of info.
Wikipedia has a special page on mud volcanoes in Azerbaijan:

'Azerbaijan has the most mud volcanoes of any country, spread broadly across the country. 350 of the 800 volcanoes of the world are in the Azerbaijani Republic. Local people call them “yanardagh” (burning mountain), “pilpila” (terrace), “gaynacha” (boiling water) and “bozdag” (grey mountain) alongside its geographical name – mud volcanoes'.

On Qobustan itself Wikipedia notes:

'Qobustan (also, Duvannaya, Duvanny, Duvannyy, Duyannaya, and Gobustan [!]) is a settlement and municipality in Baku, Azerbaijan. It has a population of 14,470'.

While the mud volcanoes themselves are located in Qobustan National Park.
Wikipedia:

'Gobustan State Reserve located west of the settlement of Gobustan, about 40 miles (64 km) southwest of the centre of Baku was established in 1966 when the region was declared as a national historical landmark of Azerbaijan in an attempt to preserve the ancient carvings, mud volcanoes and gas-stones in the region.
...
Mud volcanoes
It's estimated that 300 of the planet's estimated 700 mud volcanoes sit in Gobustan, Azerbaijan and the Caspian Sea Many geologists as well as locals and international mud tourists trek to such places as the Firuz Crater, Gobustan, Salyan and end up happily covered in mud which is thought to have medicinal qualities. In 2001 one mud volcano 15 kilometres (9.3 mi) from Baku made world headlines when it suddenly started spewing flames 15 metres (49 ft) high'.

Seems a slight mismatch with other info likewise found on Wikipedia. But let's reckon that a significant amount of the earths mud volcanoes can be found near Qobustan. 

How about the rating of a visit? Tripadvisor dolls out 4.5 stars (207 reviews), while google gives a visit 4,6 from 46 reviews.

Another first hand experience by dark-tourism by^:

^'The mud volcanoes of Qobustan are not the biggest specimens of their kind, but they are fascinating all the same. In fact, their comparatively small size has the advantage that you can get right up close – you can even touch the mud if you like (it's indeed just cold mud, as I can testify). The best bit, however, is just watching the bubbly action. And listening to it. Many of these flatulent little vents make rather suggestive noises.

How much action there will be at any given time will vary a bit, but at the very least you should be able to see some bursting gas bubbles and spluttering ejections of mud from the more virile volcano vents.

Most of them are on the top of cones some 10 to 15 feet (3 to 5 metres) high, but there is also one flat, almost perfectly circular mud lake a bit off the mud volcano cones proper.  

And if you're really into mud, you can even do so literally: go into the mud that is, namely in that same said mud lake, and wallow about in it. I've not done it myself but have seen video clips online of some quite astonishing mud-bathing – with one person even completely submersing herself in the mud only to suddenly come out looking like some horror movie zombie …

A clip:

Finally traveltoe adds:

'By reaching the Mud volcanoes, you'll see this unique wonder and not only touch, but also dive into this healing mud. Having fun with mud volcano will continue with salty lake swimming, and having cold local beer with some snacks'.