Prohibition
Factory Sealed
I prefer prohibition and while it is not impromptu necessarily it looks like it and I used it for a long long time.
Factory sealed can be done impromptu and I have attempted and succeeded however you need audience management to do this and to do that actual effect.
I still would say though Scarabaeus is the best anything through bottle. Cellphone is of course my usual choice and it's cool as hell shoving their iPhone through the bottle.
Gimmicks are not bad, you need to choose them carefully and bring the ones that you can use everyday. I brought branded and two other gimmicks with me all the time and it took up maybe half a pocket. One in my wallet, one in my pocket that was small, and another in my back pocket with my wallet.