Ordinary construction debris and household junk are welcome. The limits come from Maine state rules and from what the receiving facility will take at the gate.
Maine treats screens as a special case. The state makes it illegal to throw away cathode ray tubes and flat LCD screens, so old televisions, monitors, and laptops have to be recycled instead. Mercury-added products such as thermostats, thermometers, and fluorescent tubes fall under a separate state disposal ban and need their own drop-off.
Hazardous material stays out, full stop. That covers paint, chemicals, waste oil, pesticides, sealed drums, and any pressurized cylinder or propane tank, empty or not. Liquids of any kind are refused, and so is asbestos, friable or not.
The Hampden facility also turns away tree stumps, hot ashes, medical waste, dead animals, junk vehicles, telephone poles and railroad ties longer than six feet, and metal panels longer than eight feet. Appliances with refrigerant, shingles, clean wood, metal, and tires are all fine, though tires and appliances are usually billed per piece.
When an item doesn't clearly belong in either column, ask your account manager before it goes over the rail.