8-55. Carbonized  air  compressor  valves  should be  cleaned  by  soaking  in 1. gasoline,  followed  by  dressing  with emery 2. a  solution  of  kerosene  and mineral  oil 3. kerosene,  followed  by  a  light brushing  or  scraping 4. a  strong  soda  solution,  followed  by a  stiff  brushing 8-56. When you are inserting valves in a compressor  cylinder,  you  should  make  sure that  they  open  in  which  direction? 1. Discharge  valves  open  toward  the center  and  suction  valves  open away  from  the  center  of  the  cylinder 2. Suction  valves  open  toward  the  center and  discharge  discharge  valves  away from  the  center  of  the  cylinder 3. Discharge  valves  and  suction  valves open  toward  the  center  of  the cylinder 4. Suction  valves  and  discharge  valves open away from the center of the cylinder Questions 8-57 and 8-58 are to be judged True or False. 8-57. One  method  of  stopping  leakage  at  the threads  of  the  valve  setscrew  of  a  high pressure  compressor  is  to  wind  a  piece  of wire  solder  around  the  threads  and tighten  the  locknut  over  it. 8-59. What  material  is  used  to  repack  the filter  of  an  air  compressor  control valve? 1. Wool  or  sponge 2. Cotton  or  wool 3. Linen  or  sponge 4. Nylon  or  steel  wool 8-60. Which  of  the  following  components  of  a compressed  air  system  is  vital  for  its safe  operation? 1. Control  valve 2. Discharge  valve 3. Suction  valve 4. Relief  valve 8-61. What liquid should be used to fill the sight  flow  indicator  that  provides cylinder  lubrication  to  a  compressor which  uses  9250  Navy  Symbol  oil? 1. Distilled  water 2. Mineral  oil 3. Glycerine 4. Each of the above Question  8-62  is  to  be  judged  True  or False. 8-62. The  sight  flow  indicators  should  be filled  with  equal  parts  of  glycerine  and mineral  oil  when  the  machinery  cylinders are  lubricated  with  a  Navy  Symbol  2000 series oil. 8-58. The  manufacturer's  technical  manual should  contain  detailed  instructions for  the  adjustment  and  maintenance  of  the various  control  devices  to  the  air system  components. 54