Some people like to poke holes in the can because they think it's going to explode. It will not explode (use you're best judgement). Also, I think that if you poke holes in the can, eventually, some of the leche is going to ooze out making a watery mess. This is my opinion only, not proven. Once it's cooled, I like to add salt, because I'm really into salted things right now, so that's another option.