To try and help this cleaning process go a bit faster I decided to soak the cookie sheet in hot, soapy water and poured some vinegar in the water as well. After soaking for about an hour I went back at it. So much better! Remember, it is better to use the baking soda as a paste. Ring out the sponge as much as possible, pour the baking soda on the sheet then go to town. The corners are still a bit tough so I did end up using the scrubbing side of the sponge to get the last bit of stubborn gunk off.