Skin temperatures which cause discomfort leading to pain and damage are provided in Parsons and in ISO 7730 for discomfort and ISO 13732-3 for skin responses to contact with cold surfaces. An approximation calculation of temperature of surface of skin when in contact with a cold object can be derived from a simple model of heat transfer. When warm skin comes into contact with a cold surface, heat will be lost from the skin and skin temperature will fall. ISO 13732-3 provides thresholds for aluminium, steel, stone, nylon and wood as well as material properties that can be used to determine contact temperatures. The international standard also provides risk assessment methods and practical advice on how to determine the likely effects of skin contact with cold surfaces. Taking gloves off to work on cold metal objects (tempted by promise of improved manual dexterity) should be avoided in very cold conditions. Metal objects will cause frostbite and the possibility of sticking.