Have you ever entered an incredibly clean building, and an old receipt or something happens to fall out of your pocket, and you immediately pick it up, and maybe even feel slightly embarrassed? Now imagine if you were in a dirty building with piles of litter in every corner, people are much more unlikely to pick up garbage they drop. They have no reason to try to keep it clean, because well, there is garbage everywhere already.
It is a well-known psychological phenomenon – the cleaner a place is, the cleaner people will try to keep it. The dirtier the place is, the less people care about keeping it clean. Having a service that keeps your facility clean as possible will keep the public who enter your building wanting to keep it that way.
You can also use this method in your own house. Keep your house as clean and as organized as you can, and the people who come into your home will automatically try to keep it clean.