Looking at the pictures, there doesn’t seem to be a habit of cleaning and tidying up. My recommendation would be for you to clean that and tidy it up as best as you can and talk to everybody to try to keep it tidy after. It will be a lot of work, but the difference might be felt by them and they might want to keep it tidy and clean.

The habit must be built over time, try to talk to them to help keeping it tidy, it will not be easy and overnight, bad habits are hard to let go. But if you feel it is not good as it is, take the initiative!

Try to make a morning in saturday or sunday to be the cleaning time, or something like that. First show them how great looking it can be and then schedule the cleaning time so it does not accumulate over time.