Things were only superficially cleaned at best. Who wants to spend an entire Saturday thoroughly vacuuming the church?
The walls, door knobs and light fixtures never got wiped down, unless someone took it upon themselves to spend the extra time doing it.
I doubt that the sacrament trays were ever run through a dishwasher. They probably weren't even hand washed with dish soap. The teenage guys probably just dumped everything as fast as they could to get out of there. If there were several wards in the same building, by the third use of the day I'm sure they were germ magnets.