Anything that's mostly metallic and "tin." So...for me it's stuff like A/C shells, fridges/freezers after I pull the compressors/copper/wiring, dryers after I pull the copper-wound motors (dirty aluminum-wound ones aren't worth the time IMO, at least for the price I get), washers, dishwashers, bikes, grills...pretty much anything that's steel and not short steel or cast iron. And for any of the above stuff, I pull anything that's easy to get off/out that's non-ferrous. Sometimes I'll fill a gutted printer with screws and other odd bits of tin and toss that into the pile.