I use aluminium foil, doubled over then fashioned into a cup (usually by wrapping it around the bottom of my creon bottle). I like this because it's cheap, i can seal the top up when i get visitors or just so its not on display, but still reopen and keep using it and I can then seal it up and pop it in the rubbish when i'm done at the end of the day or when it's full, whichever comes first.