We clean offices in the evening, starting after seven, so nobody is working with a vacuum beside them.
Desks are wiped around what is on them rather than through it. Nothing on a desk is moved into a different place, nothing on a desk is thrown away, and paper is never touched. Those three rules are in the contract because they are the three complaints every office cleaner eventually gets.
Washrooms and kitchens are checked against a list and signed off, and the sheet is left in the kitchen. For an office of sixty desks the visit is about three hours with a team of three.