Dry ice can be used to remove oxygen from tanks containing flammable solvents, making them safer for repair or removal.
To remove oxygen, first put dry ice pellets or blocks into the filler opening of a tank. Then, place a dry rag into the tank opening. After several minutes, the dry ice sublimates and fills the tank with carbon dioxide gas which displaces the oxygen.
The stuffed rag allows oxygen and CO2 gases to escape, eliminating pressure buildup inside the tank from the sublimating dry ice. The amount of dry ice and wait time vary depending on the size of the tank.
After the flow of CO2 gas from the tank opening has continued for several minutes, the tank is ready for repair.