Oxygen Combustion Flask

[eces]

Hello all,
I was burning sulphur in an oxygen combustion flask and the stopper was stuck in the neck of it. How can I remove it without breaking it? Thanks in advance.

[dap]

Hello. Try to knock a bit.

[tom jupille]

Another possibility is to use a heat gun on "low" (or, even better, a hair dryer) to *gently* warm the neck of the flask. That may expand it enough to let you pull the stopper.