There are some nasty little rust stains on them from letting the dry in the dishwasher. I was looking at Buzzfeed, and came across an amazingly simple and inexpensive way to remove them, with little effort on your part! See tutorial ----> http://www.discountqueens.com/diy-rust-stain-removal/
Magic Eraser uses... did you know you can cut a piece off and float it in your toilet overnight and voila! no more toilet ring! -clean window screens (even when they are still in the window) The website has a list of about 100 uses!