Microwaves are not acceptable for garbage disposal because they contain hazardous materials such as lead, polychlorinated biphenyls (PCBs), mercury, and other toxins. Not only that, but their capacitors can cause electric shocks if damaged during disposal. Lastly, these appliances can take up a lot of space when thrown into landfills, causing potential leakage of hazardous materials into the ground and water table. Do your part and make sure to get rid of these units safely and responsibly.