The process uses dry-ice pellets forced out with compressed air to clean. The pellets hit the surface and turn to a gas that lifts the dirt and debris. The pellets hit the surface at -109degress breaking the bond of the dirt. The system we use has the ability to dial in pellet size, pellet volume, and air pressure which gives us the ability to clean the dirtiest metal or the most delicate fabric! Our machine can take ink off a business card without destroying the card itself or undercoating off the bottom of a car without damaging the metal.