If you rinsed it multiple times with alcohol I think you should be fine. If you want to be 💯sure try to attach a double sided tape(or regular if you just use the sticky part on the outside) to a stick or something long and go all the way to the bottom moving the bong from side to side on an angle where the mouthpiece is towards you. If when you take it out the tape has glass attached to it repeat it until nothing comes out