(6) If no additional flame throwers are to be filled, close pressure-cylinder valve, or stop compressor or pump. Then, using wrench, slightly loosen the air line at the drum, allowing pressure to bleed. When the pressure in the drum has fallen to that of the atmosphere, close regulator valve. (7) Roll drum slightly and gently until fuel-filling hose is at top of drum. (8) If there are valves on each end of the fuel-filling hose, use wrench to slightly loosen hose, allowing gradual escape of pressure. Stand away from, and at the side of, the connection. Keep hose pointed away from other personnel. When all pressure has been released, complete unscrewing of hose. (9) Wipe fuel-tank plug seats and the plug threads with a clean, dry cloth. Then screw in filling plug and safety-head plug assemblies, applying grease (Par 49 _b_) if plug tends to freeze to seat. Tighten with wrench. Wipe any spilled fuel from weapon. 40. PRECAUTIONS WITH FUELS. _a. Flammability._ All fuels used in flame throwers obviously are highly flammable and must be handled, stored, and used with extreme care. Diesel oil, fuel oil, and kerosene require the same care as does gasoline. _b. Indoor storage._ When it becomes necessary to handle gasoline in a room or building, the windows and doors should be open and care taken that no unprotected flame which might ignite the fumes is in the vicinity. The doors and windows should remain open for a sufficient length of time afterward to allow any vaporized gasoline to escape. _c. Flames and sparks._ The presence of open flames, heated stoves, electrical tools and apparatus, and other equipment likely to cause sparks must not be permitted. Even nails and metal cleats in shoes are a potential hazard in the presence of combustible fumes. _d. Smoking._ “No Smoking” signs must be posted in prominent places about the premises and the rule against smoking must be strictly enforced. _e. Ventilation and cleaning._ The buildings in which fuel is stored or used must be well ventilated and thoroughly cleaned every day. No rubbish or other flammable material should be permitted to remain in or near such buildings. _f. Spillage._ Care should be taken that fuel is not spilled. Any spillage should be removed promptly. _g. Safety cans._ Safety cans should be used, if possible, for storing small quantities of gasoline, as they have covers that must be forcibly held open to remove or add gasoline. _h. Rags._ Metal receptacles with metal lids should be provided for discarded, oily, or gasoline-soaked rags. These rags must be disposed of daily. _i. Electrical apparatus._ Vaporproof incandescent electric lamps, switches, and other appliances of approved type should be used. Open switches, relays, and similar apparatus, or motors with commutators, must not be used where gasoline fumes may be encountered.