Before reading this you may also want to read How To Scrap A Microwave.
The Magnetron is a device that creates arbitrary microwave radiation from a voltage source. In the case of the microwave oven, it is used to heat our food!
When you pull ones of these magnetrons out of a microwave, you can sell it at motor price along with the transformer. These two work together in a microwave; the transformer steps up the voltage to the correct level for the magnetron to be effective.
A magnetron’s efficiency is about 65%, meaning 65% of the electric power it uses is converted into EM radiation used to cook out food.
As you can see on the left, There is actually very solid components in a magnetron and no digital “electronics” in the modern sense. There are two large magnets in the magnetron, some aluminum fins that function as heat sinks, and a copper core with cavities. This copper core is often too difficult to cut out, so I recommend selling the whole thing at Copper Breakage or Motor price.
A quick warning: The pink/white output antenna ceramics may contain beryllium oxide. This can be very toxic, more so than lead, so dont smash this thing to pieces. This may be the reason a few yards do not accept microwaves all together.