Marie, is the Mr Clean safe for the pattern on the liner? (I currently have a customer with algae looking iron splothches all over her liner - I almost started a post, but gleaned enough from a previous post that you and smallpooldad had contributed to, to enable me to take a stab at it - thanks!!)
Raven, I don't doubt Marie's advice (anymore, I tried to use logic to refute her this spring, but expertise overruled logic) she really knows this stuff. I'm just worried about liners and abrasives. If the Mr Clean works, great! I usually use some pH up (or baking soda) paste on a green kitchen sponge. The stain you have is probably collected oils and a strong base will break them down, with a little elbow grease.