This phenomenon occurs due to the expansion of the compressed refrigerant liquid as it dispenses through the aerosol valve and flashes to a gas. If the aerosol is operated for a long period, frost may form on the can because it is freezing the surrounding water vapor from the air. If it is collecting on the material to be cleaned, the operator is dispensing for too long of a period or is dispensing it too close to the material. The frost will evaporate and leave no residue. However, particulate matter blown onto a sensitive surface may cause damage due to the high pressure of the duster if dispensed too closely to that surface.