Figure 4-27.—Removing locking nut

CAUTION ENSURE THAT CLEANING SOLU- TION DOES NOT ENTER THE IN- HALATION/EXHALATION VALVE ASSEMBLY. Moisten a gauze pad with the cleaning solution and wash the facepiece and housing assembly both internally and externally. After washing, the mask should be thoroughly and repeatedly rinsed with warm water. NOTE: Another alternate sanitizer, Aerosol Antiseptic Spray SBT-12 (di- bromosalicyl bromanicide), manufactured by Lever Brothers, Inc., can be used. Directions for use are indicated on the container. After all parts are dry, disinfect by using a gauze pad or other lint-free wipers, with a solution of 2 tablespoons of chlorine bleach per gallon of water; rinse with clear water and air dry. Be certain disinfectant reaches inner crevices of the faceform. To clean the delivery hose, wash it with a cleaning solution and rinse it with clear water. Allow all parts to air dry. When cleaning the inhalation/exhalation valve assembly, it will be necessary for you to obtain a container just large enough to partially submerge the valve. Fill the container half full of benzalkonium chloride solution, MIL-B-37451, or a solution of 70 percent isopropyl alcohol and 30 percent distilled water. 239.423 Figure 4-27.—Removing locking nut. By using a valve wrench, as shown in figure 4-27, unscrew the valve nut and remove the locking nut, bearing washer, and isolation washer from the inside of the mask. This will allow the valve, sealing washer, delivery tube, and connector assembly to be removed as a unit from the outside of the mask. Hold the base portion of the valve and submerge the operating portion of the valve into the solution. Normally, only a few seconds are required to remove any stains and residue. For stubborn residues, use a cotton swab saturated with benzalkonium chloride and rub lightly to remove. Gently shake excess solution from oxygen valve and allow it to air dry completely. 4-32