Hi, this is a fun idea - the expresso key ring.
This would be a high quality rigid plastic cup like we used to have on some airlines (see pic), but scaled down in size for an expresso serving.
Or it could be a rigid plastic version of a classic expresso cup design
It would have a silicone lid that covered it extremely snugly, without any hole bigger than a pinprick to let out steam - perhaps the silicone lid would resemble a mini version of one of the bigger plastic lids.
I think that when clean, it might be suitable and small enough to fit on someone's keyring, so they could enjoy an authentic expresso experience at any time.
The silicone lid would keep out any dirt etc - it would fit really tightly.
Whilst this idea is just for fun, please do vote and comment on my more serious suggestion for solving the coffee cup mountain problem at the following link:
Click on http://www.jovoto.com/contests/drink-sustainably/ideas/5046
Drink Sustainably
Solution
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