Field Day
A special day is set aside from time to time aboard a submarine for cleaning. Ironically, this day is known as “field day.” When the command “sweepers, sweepers, man your brooms!” is broadcast over the PA, sailors would collect cleaning materials and begin cleaning.
On most submarines, the sailors don’t have enough space to swing traditional brooms around, so they use sponges or hand-held brooms (foxtails) instead.