say i have a glass bottle with a glass tube with the same diameter as the hole it goes into the bottle. say the glass tube stem breaks off so its stuck inside the opening of the bottle.

if i heat both the glass bottle hole opening and the glass tube stem stuck inside the opening, what will happen? I want to use tweezers and pull the stem out once theyre heating up.

Or should i freeze them instead?

With a finger ring, u can put ice on it to loosen it up. U would think metal contracts, so when u cool it, it would tighten around ur finger. But no, its the cross section of the ring that contracts and it both increases inner diameter and reduces out diamter.