As long as you have removed the packaging now, it's not going to do any harm to the machine.
The stains will likely be permanent but won't do any harm.
Good luck with your steam oven (my wife loves her one)
Hope this helps
Let me know if you need more help with this.
There was none of the packaging left in the oven to remove. It appeared to have melted ie no trace other than the staining on the evaporator dish and 3/4 tiny, round pieces of polystyrene. Is it safe to use.
Yes, it's safe to use.
Polystyrene is mostly air.
Just give the oven a good clean (the dish too, but, as previous, you probably won't get the stains off) and use the oven.
There's not a lot in them, basically, water is pumped onto an element to produce steam.
All the cooking is done by steam.
Has the polystyrene simply melted away/evaporated or will the residue/remains be clogging up the "works"?
It's basically dissolved.
It won't clog up the works as there's no works for it to clog up.
As I said previously, water is pumped into the machine, not sucked out.
It will be fine, just clean it and use it.