It is common to see children when hurt while playing given ice packs to the injured area. Why is this coldness good? Does it numb the injured area so sensory signals less frequently reach the central nervous system? Also dry ice such as CO2 is able to 'burn' skin because of its very low temperture, not through any chemical effect. It has been used in the past by doctors to remove warts and even small skin cancers. How does dry ice 'burn' skin? How does it remove what they claim is it the burning effect? The article said that these days liquid nitrogen is used instead of CO2 as it is far colder and temporarily anaesthetises the skin - which goes back to my first question? It also burn warts and cancers more effectively.