Was prompted to share this one on a technicians' email group today and thought it might be a good tip to put here, so here goes: I don't know if anyone has ever seen the 'cork in a wine bottle' trick, but this is basically the same thing applied to the prep room, when a rubber bung has been pushed too far into the neck of a reagent bottle or flask. If the bung is still in the neck of the bottle, give it a push so it falls inside. If you can't get it all the way in, this trick won't work for you. Now follow these steps: Pour any liquid in the flask or bottle into a beaker, the bottle needs to be empty except for the offending bung. Health and safety time- if your flask or bottle has had something unpleasant in it, please give it a bit of a rinse. Insert a plastic carrier bag partway into the bottle, closed end first, keeping the end with the handles outside the bottle Tip the bottle upside down so that the bung is near the bottle opening and the plastic bag extends past the end of the bung. Inflate the plastic bag, it should inflate around and behind the bung. Pull the bag out of your flask/bottle. The bung should come out with it, wrapped in the bag. (This may take a bit of force depending on your particular bung/bottle combination. It may help to have one person hold the bottle and the other pull the bag.) I have rescued many a bung with this method!