[grhazelton]

I've just "unearthed" a cruet which I think my Grandmother bought, probably in the 1920s. It is glass with decorative work, probably hand done, and a ground glass stopper with a silver knob, probably sterling.
Sadly it seems that the cruet was put away with no oil or grease on the ground glass mating surfaces. I'm afraid to use any force for fear of breaking off the silver knob. While it may have little monetary value, it has sentimental value to me. I recall in chem lab - I did two years toward a B.S. - mating ground glass surfaces were greased, what kind of grease I don't know.
Any suggestions for removing the stopper?
Many thanks!

[MarkJerling]

I did a google search and found this: https://www.thoughtco.com/remove-a-stopper-3976101

[grhazelton]

I did a google search and found this: https://www.thoughtco.com/remove-a-stopper-3976101

Certainly worth a try! This is a trick I've used on jar lids, although a failure or damage to the lid would be far less consequential.

Many thanks,

George

[nosliwmit]

You can also try putting the whole thing in the fridge or freezer for a few hours and then setting it in a sink full of warm (not too hot) water, leaving the stopper out of the water. A little thermal expansion sometimes works wonders.

[crazy4oldcars]

Run warm water over the neck, as close to the stopper as you can get?
As was mentioned, thermal expansion is all you have to work with.


Kirk B.

[Blue]

You could try getting some mineral oil soaked in between the ground surfaces and letting it sit a while.

[Digitalis]

You could also try sweating it loose - spot heating glass is a kind of last ditch option as the risk of breaking it is very high.

I did two years toward a B.S. - mating ground glass surfaces were greased, what kind of grease I don't know.

We use all kinds of grease in the lab these days: what is used really depends upon the reagents involved and the desired reaction conditions.