A method for recovering a re-usable grade of sulphur hexafluoride from a potentially contaminated gas source including sulphur hexafluoride, said method including the steps of: cryogenically reducing the temperature of at least one extraction vessel to a temperature below phase transition of sulphur hexafluoride gas, wherein at said cryogenically reduced temperature the pressure in said at least one extraction vessel is less than the potentially contaminated source pressure fluidly connecting said at least one extraction vessel with the potentially contaminated gas source and allowing said potentially contaminated gas to enter said at least one extraction vessel due to the pressure difference between the at least one extraction vessel and the potentially contaminated gas source, the sulphur hexafluoride included in said potentially contaminated gas turning into liquid and/or solid form in said at least one extraction vessel; evacuating any non-condensed contaminant gas from said at least one extraction vessel while said at least one extraction vessel is at said cryogenically reduced temperature; raising the temperature of said at least one extraction vessel from said cryogenically reduced temperature to substantially a dewpoint temperature, wherein at said dewpoint temperature a re-usable grade of sulphur hexafluoride gas is present in said at least one extraction vessel and any condensable contaminants are in liquid and/or solid form, and wherein raising the temperature substantially to the dewpoint temperature raises the pressure in the at least one extraction vessel; cryogenically reducing the temperature of at least one recovery vessel to a temperature below phase transition of sulphur hexafluoride gas, wherein at said cryogenically reduced temperature the pressure in said at least one recovery vessel is less than the pressure in said at least one extraction vessel when substantially at said dew point temperature; and fluidly connecting said at least one recovery vessel with the at least one extraction vessel and allowing said re-usable grade of sulphur hexafluoride gas to enter said at least one recovery vessel due to the pressure difference between the at least one recovery vessel and the at least one extraction vessel. cryogenically reducing the temperature of at least one extraction vessel to a temperature below phase transition of sulphur hexafluoride gas, wherein at said cryogenically reduced temperature the pressure in said at least one extraction vessel is less than the potentially contaminated source pressure fluidly connecting said at least one extraction vessel with the potentially contaminated gas source and allowing said potentially contaminated gas to enter said at least one extraction vessel due to the pressure difference between the at least one extraction vessel and the potentially contaminated gas source, the sulphur hexafluoride included in said potentially contaminated gas turning into liquid and/or solid form in said at least one extraction vessel; evacuating any non-condensed contaminant gas from said at least one extraction vessel while said at least one extraction vessel is at said cryogenically reduced temperature; raising the temperature of said at least one extraction vessel from said cryogenically reduced temperature to substantially a dewpoint temperature, wherein at said dewpoint temperature a re-usable grade of sulphur hexafluoride gas is present in said at least one extraction vessel and any condensable contaminants are in liquid and/or solid form, and wherein raising the temperature substantially to the dewpoint temperature raises the pressure in the at least one extraction vessel; cryogenically reducing the temperature of at least one recovery vessel to a temperature below phase transition of sulphur hexafluoride gas, wherein at said cryogenically reduced temperature the pressure in said at least one recovery vessel is less than the pressure in said at least one extraction vessel when substantially at said dew point temperature; and fluidly connecting said at least one recovery vessel with the at least one extraction vessel and allowing said re-usable grade of sulphur hexafluoride gas to enter said at least one recovery vessel due to the pressure difference between the at least one recovery vessel and the at least one extraction vessel.