(1) _Opening cans._ Do not open cans containing cylinders until ready to load for a mission. (Par 18) If an extra cylinder remains in an opened can, use it as soon as possible. Any defective cylinders, such as those with damaged closure plates, should be destroyed. (Pars 30 and 46) Moisture may affect the cylinders and all possible care should be taken to avoid exposing them to dampness. (2) _Handling cylinders._ Pressure on any of the five metal matches (Fig 13) may ignite an incendiary charge in the cylinder. Care must be exercised to avoid putting pressure on the projecting ends of the matches except when firing the weapon. Ignition cylinders and cylinder containers should be protected against shock. Boxes and cans containing cylinders must not be thrown or dropped. (3) _Storing containers._ Containers of ignition cylinders are best stored in a dry, well-ventilated place, out of the direct rays of the sun, well protected against excessive temperatures. Smoking is not permitted and matches are not used where ignition cylinders are stored. 32. CHARGING PRESSURE TANK. _a. General._ The pressure tank of the flame thrower must be fully charged with compressed air or compressed nitrogen before the start of a mission. For the M2-2 flame thrower, a pressure of at least 1,700 pounds per square inch is required. This may be provided either by the use of an air compressor capable of producing a pressure of at least 1,700 pounds per square inch, or by the use of commercial cylinders. The filling and charging lines from the service kit are used in conjunction with the cylinders. Before and after charging, follow the procedures described in Paragraphs 51 and 55. _b. Charging from air compressor._ Compressor, air, gasoline engine driven, 7CFM, M1, is a self-contained, skid-mounted machine designed for use with flame throwers. It is capable of charging pressure tanks of flame throwers and large 200- or 220-cubic-foot commercial cylinders as well. Instructions for use of the compressor will be found in the manual accompanying it. _c. Charging from cylinders._ If an air compressor is not available, it is necessary to use cylinders containing nitrogen or air. (1) _Volume and pressure._ Cylinders come charged with 200 to 220 cubic feet of air or nitrogen. Since cylinders with 220 cubic feet of air or nitrogen have a higher initial pressure, it is recommended that they be procured, if obtainable. All cylinders used must have a pressure of at least 600 pounds per square inch. One or more of the cylinders must have a pressure of at least 1,800 pounds per square inch. Two or more cylinders, preferably at least four, should be used, if available. (2) _Charging capacity._ Fully charged cylinders, if properly used in rotation, have capacity for charging pressure tanks approximately as follows: