TM 1-1500-204-23-4 Figure 4-3.  Mercury Cleaning Apparatus tube with solution of strong soap and ammonia, Federal Specification O-A-445. 2 Next  swab  tube  with  a  solution of  nitric  acid,  (25  percent  acid  and  75  percent  distilled water). 3 Rinse cleaned tube with distilled water  and  dry  with  ethyl  alcohol,  Federal  Specification O-E-760, Type II. (3)  Reservoir  servicing.    Fill  reservoir  when required using the following procedures: CAUTION The fill mark is located on a plate, or  plates,  near  the  bottom  of  the manometer  scale.    Either  a  water fill  or  a  mercury  fill  plate  or  both may   be   used.      The   presence   of either or both plates indicates the materials of construction used for parts   that   come   in   contact   with the  indicating  fluid  and  indicates what fluids may safely be used in the   manometer.      Improper   fluid may cause damage to manometer. (a)   Remove   fill   plug   from   well   and ensure drain plug is tight. (b)  Pour  indicating  fluid  into  the  well to  bring  level  up  to  the  fill  mark  designated  by  the  fill plate of the liquid being used. NOTE Keep  manometer  reservoirs  filled to    specified    level    (mercury    or water).  When water is used, add a small  amount  of  aniline  dye,  MIL- A-10450  (usually  red),  to  facilitate quick and accurate readings. (4)   Operating   procedures.      With   suitable connections  made  and  the  manometer  adjusted,  apply pressure    (or    vacuum)    to    the    manometer    and    the instrument  being  tested.    Gradually  apply  the  pressure covering     the     entire     instrument     range     and     record comparative readings.  Refer to TM 55-6685-201-12. (5)  Safety  practices.      All   of   the   cleaning agents  except  water  are  toxic  and  should  be  used  with care. WARNING All     except     water     and     carbon tetrachloride are highly flammable.  Use in well-ventilated area,   avoid   inhalation   of   fumes and  skin  contact.    When  mixing acid   and   water   together,   always pour    the    acid    into    the    water. Never pour water into acid.  Avoid skin   contact   with   the   acid   and with    the    mixture.        Avoid    skin contact  with  the  alcohol  used  for a rinse.  Do not drink the alcohol: acute     illness     and     death     may result. (6)    Mercury    spill    procedures.        Do    the following whenever mercury is spilled: (a)   Deactivate   equipment,   give   the alarm,   and   activate   exhaust   systems   which   exhaust room air to the outside. (b) Deactivate air-conditioning systems.      Close   vents   and   doors   that   would   allow mercury fumes and vapors to enter other work areas. (c) Leave the area and take action to assure that personnel are kept out of the contaminated area. Change 3  4-4