Last week I took advantage of the lifetime guarantee and replaced my entire set of All Clad. Williams Sonoma honoured the guarantee. BUT, they gave me a hard time because they thought that I was putting it in the dishwasher. I wash my pots by hand. I never use abrasive sponges. Just as I was about the load my new set into my car, the woman told me that I should never use cooking sprays on my cookware. I have googled and searched this board and haven't found any information to back this up. I also checked All Clad's website and didn't find a reference to this warning. Has anyone else been told this with regard to high quality cookware?