I used my 4-month-old Calph hard anodized chef pan with no oil or non-stick spray. My food melded to the pan. I boiled water in it for a while, scrubbed with a scrubbie, scrubbed with BarKeep's friend, and then gave up. I got most of it off, but I am sure my pot is not immaculately clean. Any suggestions for avoiding this in the future? Is it imperative to use oil in an anodized pan? Is it safe to use cooking spray? Thanks!