Unlike other blast media, dry ice has a temperature of -109°F (-78.3°C). Because of the temperature difference between the dry ice particles and the surface being treated, thermal shock occurs during the process of dry ice blasting. This causes a breakdown of the bond between two dissimilar materials.
Contaminants can be dry, wet, hard or soft. Dry contaminates will break up into small chips and can be swept up or vacuumed. If the particles are large enough, they do not become airborne. If the contaminate is wet, such as grease or oils, the stream will move or push the liquid away much like a high pressure water stream would, except that the surface where the contaminate was will be dry and clean. To prevent redeposition, the operator should work in a methodical way, from the top down.