Unplug the microwave oven
Remove any food, trays, and accessories
Check local waste disposal rules
See if the manufacturer offers take-back or recycling options
Take it to an electronics recycling center
Drop it off at a household hazardous waste facility if required
Use a municipal bulk waste pickup service if available
Donate it only if it is working and safe
Remove personal labels or data if applicable
Do not put it in regular trash unless local rules allow it