removing stuck glass stopper

[Lord Refa]

any suggestions? have a couple of stoppers (one bottle, one sep flask) that I can't get the stoppers off... thanks

[Xylene]

I've had that happen a few times with volumetric flasks that have not been used for considerable time. The preventive solution is to lubricate the middle taper of the ground-glass stopper with smallest possible film of silicone grease using a tooth-pick as an applicator. Then while replacing the stopper, rotate it couple times to distribute the thin grease film. This greatly reduces the tendency to stick, especially ground-glass joints of hot boiling flasks after they cool down.

In your present case:
Pop out your stuck stoppers by immersing the bulb of the flask in very hot water..previously wrapping the neck and stopper with a wash-cloth (or small rag) to prevent the glass stopper from being thrown like the cork from a toy pop-gun.

In the case of your Sep. funnel, close the valve before heating as described, as you must seal in the expanding hot air for this method to work.

[jacobavera]

corning has a better way. soak in fresh soda pop. then heat it.
http://catalog2.corning.com/Lifescience ... |Glassware