I don't know how much trouble this could be to code, but my idea is to make rooms cleanable. It could simply a set of twin @messages one that is the dirty description and the other is a clean one.
And to be able to clean the room you should need a mop and a bucket of cleaner. So depending on how many days the room is left without cleaning, the more times you have to 'use mop on bucket' and 'use mop on room'.
And the next day the description would change back to the dirty one.
Cheers.