Talking to my new housemate. I say: People like to hoard and store stuff sometimes, but we try to keep it a neat and clean place here. So, please don't do that here. Especially for/with/in the refrigerator. Please throw away food that's expired or you're never going to eat. Thank you.
Can all be used?
I'd use "with" or "in" the refrigerator.
We try to keep things clean and tidy here, especially in/with the fridge. Please get rid of stuff that's gone off or which you're not going to eat.
Personally, I wouldn't say "food that's expired". If it's actually mouldy, it should be thrown away. However, many foods are perfectly edible long after their "sell by date" so I wouldn't insist that people throw away food after that date, only once a food is actually inedible.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.