Instantly reminded my of the Saturator my friend told me about when she was growing up in Poland. It was basically a cart that trundled around with a Soda fountain. There would be one cup tied to the cart. You payed your money and got the cup with Soda, with the choice to add Rasperry syrup. Then the vendor would wipe it out with a rag and serve the next person. (She definitely remembers them still being around at least as far as the 1980s)
