What is that black stuff that builds up on cooking sheets after heavy use? Why is it so difficult to clean? Is it possible to clean it off completely?
It’s just carbon. Burn just about any food enough and that’s what you’re left with. White vinegar and dish soap gets it off after a good soak. Oven cleaner is harsher but works a lot faster
You can think of it as ash from burnt on food bits. I’ve never tried it myself but I’ve heard using oven cleaner is a surefire method of cleaning it off.
Don’t clean it off!
Darker coloured cooking sheets absorb the infrared radiation of your oven elements better than light shiny ones. These will give you a better browning.
Feel free to watch this video for more information about it.
It’s mostly carbon. You get tiny bits of it burnt on when you cook and because it’s chemically neutral it’s very resistant to soaps and detergents. You can scrape it off with a lot of work but you might damage the baking sheets in the process.