Cleaning of oil purifiers is another regular task.

On diesel and gas turbine propulsion plants the Second is in charge of auxiliary boilers, auxiliary engines, incinerator, air compressors, fuel, and fuel oil purifiers.

An Oil Purifier or Vacuum dehydrator is used to extend oil life, reduce frequent oil disposal, remove dirt, gases, free and emulsified water from many types of oils.

Machinist's Mates (MM) operate and maintain steam turbines and reduction gears used for ship propulsion and auxiliary machinery such as turbogenerators, pumps and oil purifiers.

Engine department trainees avail of a fully functional engine room, which includes diesel engines, oil purifiers, air compressors, sewage treatment plant, fresh water generators and other equipment found on board oceangoing vessels.