From Roy Chapman Andrews' excellent book 'Across Mongolian Plains' published in 1921.

In the careless freedom of his magnificent horseman-ship a Mongol seems as much an untamed creature of the plains as does the eagle itself which soars above his yurt. Independence breathes in every movement; even in his rough good humour and in the barbaric splendour of the native dress.

But the little matter of cleanliness is of no importance in his scheme of life. When a meal has been eaten, the wooden bowl is licked clean with the tongue; it is seldom washed. Every man and woman usually carries through life the bodily dirt which has accumulated in childhood, unless it is removed by some accident or by the wear of years. One can be morally certain that it will never be washed off by design or water. Perhaps the native is not altogether to blame, for, except in the north, water is not abundant. It can be found on the plains and in the Gobi Desert only at wells and an occasional pond, and on the march it is too precious to be wasted in the useless process of bathing. Moreover, from September until May the bitter winds which sweep down from the Siberian steppes furnish an unpleasant temperature in which to take a bath.

The Mongol's food consists almost entirely of mutton, cheese, and tea. Like all northern people, he needs an abundance of fat, and sheep supply his wants. There is always more or less grease distributed about his clothes and person, and when Mongols are en masse the odor of mutton and unwashed humanity is well-nigh over-powering.

I must admit that in morality the Mongol is but little better off than in personal cleanliness. A man may have only one lawful wife, but may keep as many concubines as his means allow, all of whom live with the members of the family in the single room of the yurt. Adultery is openly practiced, apparently without prejudice to either party, and polyandry is not unusual in the more remote parts of the country.

The Mongol is unmoral rather than immoral. He lives like an untaught child of nature and the sense of modesty or decency, as we conceive it, does not enter into his scheme of life.