Honourable Jester posted this good point about using cleanliness as a handy way to make things seem creepy or wrong in horror. Just make something incongruously neat or clean. Here is the list of some examples:
Source: Honourable Jester
Cleanliness Can Be Creepy in Horror
Sounds a bit like the old adage, “Never trust a restaurant that’s too clean.” If they have that much time to get everything nice and neat, it’s because they don’t get enough customers. Ergo, the food must be terrible!