Hi all, I have a lecreuset cast iron shallow casserole that came with the husband. I’ve tried using it a few times and absolutely everything sticks to it. It’s taking up cupboard space and is currently unusable. Is there anything I can do to restore the surface? I don’t know why it’s in this state, my ancient ones from Sainsbury’s go through the dishwasher and don’t stick. Any ideas or shall I (responsibly) bin it?