When I started canning this year, I'd bought a bunch of jars from Walmart when they were on sale. Easy-Peasy.
A few months ago SM was given a TON of free jars from a fellow whose elderly Mother had passed away. I've been slowly going through her jars. Many of them are hazy. Does that matter? And I noticed with my last batch that I ran through the dishwasher for prep that they still weren't coming up clean. Little flecks of crud inside and out. (Understandable considering that none of us will see so good close up as we get older.)
Anyway, logic always says that if you get a hand-me-down item, expect to need to spiff it up at bit before use.
This appears to be rust. (Looks like somebody left her rings on.) A good hand washing wasn't even removing it so I pulled out the "big guns".
I've reviewed these "magic erasers" before and I'll shout it from the highest roof top. "These things ROCK!" Any kind of stubborn stain, mark, grit or crud, pulls right up with a swipe or two of the magic eraser.
I can't even begin to imagine life with my messy stove top without them.
Truly a miracle of the 21st century.