I've only had one, I packed it full of other plastic and took it to the spring clean-up drop off day. I've got another one out there that's been around for years, all metal body, stainless steel in places, I'd of guessed it had copper wound motor but nope, was by there yesterday and took my pocket knife to it, nothin but aluminum.
You might could advertise those plastic shells for free, or maybe a buck apiece or something, might get rid of quite a few like that