Jewish wine in non-Jewish jugs - there's a dispute over how prohibited the wine is, and under what conditions. But if there's a Jewish intermediary, that might increase the possibilities. With the perpetual concern being a non-Jew pouring a libation that the Jew might not even notice. Also, Rav Zevid's take on non-Jews tossing things into the wine of the Jews - at what cost? But how did people handle the expense of not using the jugs or other vessels. Also, fish stew and cheese -- how they cooked and how they spiced their food, and so on. With a reduced halakhic concern, as long as no wine is entering the soup, for example. Or calves that were dedicated to idolatry, for example, when they are then used to make cheese.