The phrase "to clean the box" means to tidy up or organize a specific area or container.
Sentences with «to clean the box»
Clean your box daily and you'll probably love it as much as I do. (healthy-pet.com)
He is working on a prototype clean box with a built - in robot that can cut open and analyze the rocks so people aren't directly involved. (discovermagazine.com)
A rule of thumb: Clean the box at least once daily, twice if there's more than one cat in the house. (pets.webmd.com)