Cold joke

Before I forget this funny joke I'm gonna tell it here before I sleep. Hehe.

Audrey was trying to open a glass jar just now. And then she asked for my help. So I tried with bare hands, with my T-shirt and then finally with wet table cloth. But, all failed. Then after a while this is our conversation:

Me: Bring it to the lab to use Bunsen burner to heat up the cap a bit so that it's easier to be opened lo...
Audrey: Nevermind la. Just leave it.
Me: Oh I know how liao! Blow your breath on the cap la.. Then the warmth can loosen it a bit.
Audrey: *Sweat*

Hehe.. I think it's a funny cold joke.