What to do?

[Anonymous]

STOP cleaning.

Request a meeting to discuss your contract.

In the mean time, look for a new job.

These people are fucking disgusting.

[Anonymous]

It is not your responsibility OP, but as a neat freak myself, I would probably clean it up if there was any down time in my day. That's just how I do things. I cannot stand clutter.

They probably will start expecting you to do it though which can be creating a monster.

It's up to you.
It's your call.