How do you open the top of a pitcher that's stuck?

things expand when hot and shrink when cold. dont set the top in hot water overnight, that will heat the inside as well as the top. try this: place it in the fridge for a few hours, so the whole thing is cold. then run hot water over the top or set it in hot water with the top down. but only for a minute or 2. see if it works. if not, run hot water over the top for another couple of minutes and try again. this is so the pitcher remain cold, while the top is warm. so it should beceome loose.