Coolant
Refrigerators, coolant and certified technicians
A refrigerator that still holds coolant has to be handled by certified technicians, because appliance disposal done the wrong way can harm the environment.
That is also why refrigerator removal counts as special handling when a job is priced. What remains once the coolant is out is mostly metal: EPA durable goods data list steel as the main material in major appliances like refrigerators and washers.