Add 2 tablespoons of baking soda to your normal dish washing liquid, and apply the mixture to the burned food. Scrub the dish with a scouring pad.
Mix one part vinegar with four parts water, and pour the solution into the casserole dish. Boil the water and vinegar solution over low heat for 5 minutes. After letting the dish cool, you will be able to wipe away the burnt food.
Wet the casserole dish, and sprinkle salt over the burnt food. Let the salt soak for up to 10 minutes, then scrub the pan using a scouring pad.
Chill the casserole dish in the freezer for 3 hours. The burnt food will be easier to remove when it is frozen, using your usual dish washing liquid and a scouring pad.
Fill the casserole dish with hot water, and place a dryer sheet inside. Let the sheet soak overnight and then wipe away the burnt food the next day.
Fill the casserole dish with hot water and a few drops of liquid fabric softener. After soaking it for 1 hour, wipe away the burnt food with a scouring pad.