The best is pure isopropyl alcohol, it is much superior to the methanol which is used in the cheaper dry gas products. The key to it's usage is to use it when the days are slightly warm and the nights cold as this is when condensation is likely to form inside the fuel tank. Also by keeping the fuel tanks more full the surface area for the condensation to form is reduced thereby reducing the water vapor liquids in the fuel. When already frozen, lines need to be thawed in a garage. Additionally, a 1/4 cup of acetone enhances the miscibility of the fuel mixture and is harmless to the lines and injectors or carburetor. Most auto parts carry acetone as a painting thinner as does Wal-Mart.
