Used it for the first time ...coated it with olive oil and added onions and celery than heated the pan....after they were well sauteed, ride to clean the pan with soap and water but the entire bottom has black chunks of flaky stuff all over. Have I ruined it? Tried soaking overnight and cleaning again. Not sure if I shoukd scrape this stuff off? If I try to cook with it, will this get into my food? What is the best thing to do? And gave I done anything incorrectly? Help! There is so much conflicting information I am not sure what to do.