Unplug the cord from the wall, wait for the toaster to cool and then remove the tray from inside the toaster oven. Hit the tray firmly against the inside of your trashcan, knocking loose any debris or burned-on food stuck to the surface of the tray.
Fill your kitchen sink with a few drops of degreasing dish soap and warm water. Drop the tray in the sudsy solution and let the tray set for a few minutes. Scrub the tray with a nylon scrub brush, which should loosen any burned-on foods and clean away burn marks.
Scrub the rack of the toaster oven with degreaser dish soap and warm water. If the rack is permanently attached to the oven, scrub the solution on with a scrub brush and wipe with a damp cloth. If the tray comes loose, wash it in the kitchen sink.
Mix equal parts distilled white vinegar and water in a spray bottle. Spray the solution on any burned marks on the outside of the toaster oven. Scrub the solution with the nylon scrub brush and wipe off any residue with a damp cloth. If the stains persist, rub the solution on and let it set for five minutes before scrubbing.
Rub baking soda on any remaining burned marks or stains. Rub a damp cloth over the stain, using the baking soda as an abrasive that lifts off the stain. Wipe off the residue with a damp cloth and dry with a fresh cloth.