TM 10-3930-664-24 (2) Keep major components and assemblies together whenever possible and practical. (3) Tag hoses, electrical wires, cables and harnesses to identify them and aid in installation. (4) Have all the necessary parts, tools, material and personnel before starting procedure. (5) Keep related parts together for identification purposes. (6) To prevent loss, temporarily reinstall attaching hardware such as screws,  bolts, washers and nuts. (7) Cap all hydraulic or other fluid lines and fittings when disconnected. (8) Only disassemble to point of problem. (9) Make sure parts are clean and lubricated before assembly. 1-24. GENERAL REPAIR PRACTICES. a. Replacement of Parts.  Only replace unserviceable parts or parts which must be discarded.  Always discard the following: cotter pins, lockwire, lockwashers, locknuts, preformed packings, rubber seals and gaskets. b. Cleaning.  Cleaning is a necessary part of most tasks.  Use the following guidelines when cleaning: WARNING Dry cleaning solvent P-D-680 is toxic and flammable.  Wear protective goggles and gloves and use in a well ventilated area.  Avoid contact  with  skin,  eyes,  and  clothes  and  do  not  breathe  vapors. Do not use near open flame or excessive heat.  The flash point is +100 to 138°F (+38 to 50°C).  If you  become  dizzy  while  using  the  solvent,  get  fresh  air  immediately  and  get  medical  aid.    If contact with eyes is made, wash your eyes with water and get medical aid immediately. (1) Use dry cleaning solvent P-D-680 for cleaning metal parts only. (2) Use a mild detergent solution for cleaning rubber, plastic and nylon parts. WARNING Isopropyl alcohol is flammable.  Inhalation of vapors can cause dizziness and headache.  Contact with  skin  may  cause  irritation.    Keep  isopropyl  alcohol  away  from  open  flame  or  any  spark (ignition  source).    Keep  at  least  a  B-C  fire  extinguisher  within  easy  reach  when  working  with isopropyl  alcohol.    Post  signs  that  read  "NO  SMOKING  WITHIN  50  FEET"  when  working  with isopropyl alcohol.  Ensure adequate ventilation.  If vapors cause drowsiness, go to fresh air.  If liquid contacts skin or eyes, immediately flush affected areas thoroughly with water. (3) Use isopropyl alcohol for cleaning electrical connector pins, wire end leads,  and switch contacts. 1-36