Originally Posted by
violist
Nah, as long as you keep the unopened commercially-packaged can totally
submerged (some say substantially submerged, but I fear for my life and
limb too much to test this), you're fine.
I am not trying to disparage all these great ideas on how to heat food in hotel rooms, I am just saying that the safety margins for heating closed food containers are slimmer than many may think. Everyone here is old enough to decide what risks to take.
BTW, the recipe for dulce de leche you are quoting has a bold safety warning about not trying to open the can while it's hot.