glass is back!   this solution working with cold and warm drinks.  See what you drink and how much is left :)

As soda and soft drinks coffee and teas sellers offers Deposit takeaway cups.
These takeaway cups can be brands own or someone else's finished products.    Glass & plastic cups are truly sustainable and theirs recycling system is already built.  In this solution customer do not need to throw away cups anymore. This is stylish to carry around and you can use glass part separate at home or work. 

When is time to buy new  cup: Customer come back to seller and gives old cup back. Seller give discount for new cup ( or money back if customer wont buy new cup )

Glass, at least in Finland will not be thrown away. It returning 99.6% for recycling.

It is certain and true that one solution will not be accepted gladly. Take way culture is a commercial activity, and sellers should be possible to customize the product to  own purpose (customer also want to show own personality in the product).  As like the soft-drink bottles, but the recycling are taken into very well.

My concept is the built  around of Iittala Hot and Cool  glass.  It is an example of how the pledged takeaway cup could look like.