If you fill an oil lamp with a smoky potion of oil, it will be transformed into a magic lamp with the usual djinni generation probability.

Ghosts and djinni can emerge from any bottle, not just potions with the randomized smoky and milky appearance. The rate at which they emerge is cut accordingly.

Either guarantee that the potion of healing will be smoky for Healers, or guarantee that it will never be smoky. Guaranteeing them to be smoky is basically an open invitation to startscum them, though.

Make djinn genocidable. If djinn have been genocided, they will not come out of smoky potions, so this can be used to ensure that your smoky potions of full healing will work properly.

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.

If you get a djinni by quaffing a smoky potion, one of the possible outcomes is that it uses its wish for itself, then is hostile.

Assuming the game supports creating temporary regions of non-poisonous gas clouds: New “smoke bomb” potion. It makes you choke/vomit when quaffed. Intended to be thrown; where it shatters, most of the surrounding terrain will be transformed into cloud.

Vanilla has since added non-poisonous gas clouds (for things such as mist from zapping fire over water), and this effect could work just as well by breaking a smoky potion, instead of adding a new object.

There is a cap on the number of smoky-potion wish-granting djinni that can appear in one game.