I posted about this a couple years ago, but wanted to emphasize how handy this is!
If you have a porcelain kitchen sink, which, most of us do....You likely have this problem often. Gross scratched up, dinged up, dirty looking sink. Even though it's "clean," it's been beat up.
Gunk and dents build up and makes it look so old.
But this is my solution. It's favorite. I use it for the bathtub too..
Barkeepers Friend Liquid rubbed into the porcelain with a magic eraser ( Buy them from the dollar tree! 2 pack for a buck )
And voila. It's new again. Buffs and cleans!