Comment Re:it tingles (Score 5, Informative) 182
In my old job we used a lot of liquid nitrogen - mainly to transfer carbon dioxide around in various scientific apparatus (a mass spectrometer, for one).
Anyone who has worked extensively with the stuff will tell you it is NOT safe unless you are careful. The Leidenfrost effect works... for a relatively short duration. But the co it used application of liquid nitrogen to a specific area rapidly cools the immediate surroundings, and then the effect stops working - especially if the nitrogen doesn't have a way to skitter away on that layer of gas (if you were to pour it into a cupped palm, for example).
Also, small droplets (such as are generated from the stuff boiling when you're freezing carbon dioxide into a cold finger) don't seem to have much difficulty reaching one's skin, Leidenfrost or no. Most of us in the lab frequently had small burns on the thumb sides of our hands.