removing bungs from flasks / tubes

We had a few conical flasks back from a lesson with bungs stuck in them. My technician decided to heat the flasks with a bunsen burner to pop the bung out. One exploded! The bang was very impressive - he's fine, he used a visor, screen and kept his distance.

So.... do you have any less explosive ideas to remove bungs?
 
Plastic bag "cork in a wine bottle" trick!
Insert a (hole-free) plastic bag into flask behind the bung, inflate, pull it out and the bung comes too!

 
We had a few conical flasks back from a lesson with bungs stuck in them. My technician decided to heat the flasks with a bunsen burner to pop the bung out. One exploded! The bang was very impressive - he's fine, he used a visor, screen and kept his distance.

So.... do you have any less explosive ideas to remove bungs?
All too often it is a chuck it in the bin hard and rescue the bung. I've tried the boiling water which rarely works. Gingerly massaging and pushing the bung away from the glass sometimes works.
 
I have carefully teased some out using a scalpel or other such thin object. Using WD40 as a lubricant can help. Not had any luck with the heating approach.
 

CovTech

Lvl 37 Alchemist
COMMITTEE
Conical flask costs around 1.20 each
Technician that spends more than much more than 8mins rescuing the bung has spent more on wages than a replacement flask would have cost

Hit the neck with a hammer, carefully pick the bung out and move on ;)
 
Conical flask costs around 1.20 each
Technician that spends more than much more than 8mins rescuing the bung has spent more on wages than a replacement flask would have cost

Hit the neck with a hammer, carefully pick the bung out and move on ;)
Ah, but don't forget the technician time spent putting in the order for a new one, unpacking it, and time spent explaining why a class is one conical flask short!

(I do agree really, unless you are trying to get it out to prove to yourself you can and/or have nothing better to do, it's not worth the time and effort.)
 
Plastic bag or balloon. Insert into flask. Slightly invert flask so bung so it is at the neck end with bag/balloon behind it. Inflate bag/balloon. Pull on bag/balloon and draw bung through the neck. It can take a couple of goes to get the angle of the bung right for it to pull free but this technique does work. Very stubborn bungs I add a little washing up liquid around the neck of the bottle as lubricant.
 
tbh we just chuck the lot, it doesnt seem worth the hassle and risk getting out a stuck in bung. Id definitely retrieve it and save the cost if there was an easy foolproof way that took seconds though
 
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