Officially, anything not maintained by CokeComm may be thrown out of the fridge. Unofficially, anything not named and dated may be thrown out, especially if it starts smelling bad (at which time it should definitely be thrown out).
The last fridge cleaning occurred in February of 1994, at which time the inside and door front of the fridge were thoroughly scrubbed with bleach-based cleanser. If you clean the fridge out, do not forget to empty the water-collection tray located beneath it. Feel free to use the gloves, sponges, bucket and cleanser located on the fridge.