out-of-hours floor work
https://blast-wiki.win/index.php/When_to_Use_Wood_Floor_Filling_vs._Replacing_Boards
After the last office doors close and the janitorial carts roll in, out-of-hours floor work becomes a quiet ritual—polishing marble lobbies to a gleam or scraping gum off sidewalk tiles under the buzz of streetlights, done by workers who see a city's tired surface when everyone else is asleep.