I made flapjacks.. took them out of the oven at the right time and thought, oh they look really wet, Chuck them back in for 4 mins.. did so... let them cool and came back to slice them up. They were supposed to be gooey and delicious. Instead they're like rocks... I chiselled some out (and they tasted great!!) but the rest are firmly stuck in the tin. Any magic ideas as to how to remove them?!