How to clean baking and cookie sheets to look almost like new?

baking soda+vinegar +dawn ...over night--2 days

Another option is baking soda and peroixide and more baking soda. Let sit for a couple of hours then wipe off with a coarse scrubbing cloth. Rinse well and it all the "gunk" isn't off then use a soapy steel wool pad. Always wash well with dishwashing soap and rinse and rinse. This is for the cookie sheets that are not treated in any way such as teflon, etc. Hope this makes yours shine:)

Brillo pads and scrub.

toss them get new ones

Me clean eraser

Baking soda sprinkled lightly, all over the inside of the pan. Then add 1/4 cup of vinegar and let it bubble. It needs to sit with the mixture in it for 4-8 hours. Pour off the dirty liquid. Then make a paste of baking soda and vinegar and start scrubbing. You may need an old dinner knife to peck away at the corners. Make more paste if the first gets black and gunky. As you get tired of scrubbing the inside of the pan, flip it over and clean the sides and bottom of the pan. I use a green scrubbing sponge. You may prefer steel wool. Either way, it will take a lot of elbow grease. Best wishes ☺️

Scrub with baking soda. But why bother?