First try scotch pad and Barkeepers friend, Ajax, or comet type stuff on the lid. About the grates. Mine were in similar fashion, and I chiseled, and grinded all the rusted and flakey enamel off, seasoned them with oil or tallow, and now treat them like a cast iron skillet. They are working fine. I wish I had a before picture, but this is one I just rehabbed yesterday - It was a rusted up mess. I have done about a dozen Qs, they all suffer the same problem, and I have managed to save them all so far. I think you could also if you want to put some time in.