This reminds me of my Navy days on an aircraft carrier. There were two open decks, open to the wind and whatnot; the flight deck and below it the hangar deck. The hangar deck was open due to the elevators on the sides that took the airplanes between the two decks.
The airplanes would drip hydraulic fluid, as well as aviation fuel. A lot of guys spit, and would spit on the deck when on an open deck.
As you can imagine, the bottom of your shoes or boots were pretty nasty.
In our sleeping (berthing) area you kept your shoes or boots on and when you went to the shower you wore flip flops. Some guy had the job of mopping and polishing the floor in the berthing area, every day. But five minutes after it dried guys would be walking on it again.
Some guys would walk around the berthing area in their bare feet. I thought that was really bizarre.