Surely there are a thousand abandoned microwaves in the city nearest you.  People leave them either at the curb (if the city will accept old appliances), at computer/electronics recycling depots, charity drop-offs, and, of course the dump itself.  Don't forget garage sales: it is almost spring, you know.  Your mission (should you choose to accept it) is to find and eviscerate as many as necessary!
Steven Fahey