Abstract: Apparatus and a method for controlling vermin either directly or indirectly via objects giving shelter to the vermin. Cooling of the vermin is effected by providing dry snow particles by passing pressurized carbon dioxide through a nozzle directed at the vermin. Smaller and larger snow particle sizes are allocated within a selected range of sizes and velocities. Environmentally friendly and rapid control of the vermin is achieved, and an effectively functioning cooling system is provided, which, by the gradual supply of snow, executes cooling through different velocities and sizes of the snow particles. In a initial cooling phase small snow particles provide cooling by sublimating and giving off cold rapidly. Larger snow particles then penetrate through the gas barrier that is created by the sublimating small snow particles to maintain the cooling effect.