Real cool gimmick. But not for children!

Have a buddy with some of the white Substanzs (feels like wool) done in the ashtray. Unfortunately, there is something striking as it is snow white and stands out easily in contrast with the black ash. But if you hide something under the ashes fällts actually really ned on. Did the first time, unfortunately, something taken too little, so the effect was not exactly (except for a brief hiss and a few smaller sparks) outstanding. Did the second attempt then hides the entire contents as a whole in the ashtray and after my mate his cigarette (not knowing) expressed therein gabs first time a faint hiss and a millisecond a 15-20 centimeters high (not hot) blue / violete flame. My friend hats carved almost backwards off his chair in shock. As would have been enough half :) A really funny joke. However, not suitable for children under 14 years because you can do so too much nonsense.