daf bit: Avodah Zarah 75

As we near the end of this tractate, the discussion turns to cooking utensils that belonged to idolaters. The rabbis taught: if an Israelite buys utensils from an idolater, unused items are immersed in the mikvah and are then fit for use. Those that were used for cold items only are rinsed and immersed and are then fit. But for items that were used for hot foods it's more complicated. Kettles, heating vessels, and the like must be scalded; utensils used with fire (like spits) must be made white-hot; either way they must then be immersed and are then fit. (75b)

These are also the methods to kasher an item that has been made non-kosher (like if you accidentally use a meat utensil for dairy). Some things can't be kashered, like wooden spoons (too absorbent), and I assume we therefore can't get them used from idolaters at least if they've been used for hot foods. For cold, I don't know.

Today's daf is 73.