If you want to poison yourself buy one!
I have purchased a Monika melodica half a year ago. These instruments are made in former GDR and in general these are high quality instruments made of wood. They are really built like a small proportioned keyboard side of an accordion. They have four reed plates with one reed for inhale and another reed for exhale, and what is best, they have a removable reed block, so you can tune the reeds outside of the instrument. You can open them easily just by removing four pins that attach the cover to the body.
These are the pro’s, and there is only one con: the reed plates are made of zinc and react with water, I think it’s called zinc pest, nice word, isn’t it? And you won’t like it, especially when inhaling! I got a beautiful rash in my mouth nearly immediately. So of course I sent it back…
So if you find a cheap Monika (or whatever it may be called) just for examining the construction, buy it, it’ll be worth it. But please don’t play!