TM  10-3930-643-34 ENGINE,  FUEL,  EXHAUST  AND 4-6. Rocker  Arm  Assembly COOLING   TROUBLESHOOTING and  Valve  Cover.  (Sheet CLEANING/INSPECTION l TOXIC/FLAMMABLE Dry  cleaning  solvent  P-D-680,  used for cleaning parts, is toxic and flammable. Use  only  in  well ventilated  areas.  Wear  protective goggles and gloves. Do not smoke or allow open flames or sparks in areas where cleaning solvent is used or stored. Avoid contact with eyes, skin or clothing. If contact with eyes is made, flush with cold water and seek medical attention  immediately. If contact with skin or clothing is made, flush with cold water. If  you become  dizzy  while  using  cleaning solvent, get fresh air immediately. l COMPRESSED  AIR  HAZARD Compressed air used for cleaning purposes will not exceed 30 psi. Use only with effective chip guarding and personal protective equipment  (goggles/shield,  gloves, etc.). 10. Clean all parts with cleaning solvent P-D-680. Dry thoroughly with compressed air. Refer to paragraph 2-8. 11. Inspect shaft (22) for rocker arm wear and on flat surface for straightness. Replace shaft (22) if worn or bent. AND  MAINTENANCE.  (cont) 4 of 9) Go to sheet 5 4-54