Cork for glass instruments
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What should be done if the stoppers of glass instruments such as burettes and volumetric flasks are clogged (and cannot be rotated)?
1. Try soaking it in water at around 80 degrees Celsius. 2. Gently tap the wooden utensil. 3. Freeze it. 4. Use a hair dryer to warm it slowly. There are many methods; in general, the idea is to take advantage of the thermal expansion and contraction of glass, while also ensuring safety
It’s also fine to vibrate it with ultrasound.
Ordinary glass instruments tend to get stuck to solutions like sodium hydroxide; for items such as Kjeldahl flasks, you can try: 1. Soaking them in water at around 80 degrees Celsius, or 2. Using an ultrasonic cleaner for cleaning
Generally, I heat the stuck cork in a water bath for 1-2 hours, and then tap it a few times with a rubber rod; that usually solves the problem
Soak it in hot water; if that doesn’t work, it might be beyond repair. Therefore, it’s recommended to wrap it in paper after use
We usually use a hair dryer first, and then gently tap it with a cork hammer
If it’s stuck to organic matter, consider soaking it in acetone before knocking on it； If it gets stuck to an alkali, it’s basically beyond repair.