boiling condensed milk...how to?

[bonzo77]

For millionaires' shortbread. The tin says to heat with sugar and some other things. Which I cocked up last time. But I've been told on here to simmer it in the can for several hours. But the tin warns me not to in case it explodes! So do I pierce it first, or any other suggestions?

I've heard stories - on here, I think - of tins exploding, but it's never happened to me or anyone I know.

No, you don't pierce it.

It only explodes if you let it boil dry. Keep it topped up with boiling water, and don't pierce it. Let it cool before opening it.

Just buy the ready boiled stuff! Carnation make it in a tin and it tastes the same.