Some method by which you can capture a djinni into a smoky potion or oil lamp (which in the latter case makes it a magic lamp). It should be non-trivial or somehow costly to do (the original idea just suggested applying the object in their direction, which is abusable). If feasible, the djinni should be angry and disinclined to grant a wish when it’s released.

Also, the game doesn’t track whether a given smoky potion contains a djinni (it would mess with stacking), so this would be tricky to implement internally for smoky potions.