Some toaster ovens that clean themselves use steam to clean the inside. Toaster oven parts could be melted if you use a handheld steamer, therefore avoid doing so.
When cleaning, you can use a little steam, but be careful. This technique involves heating up a 1:1 mixture of distilled white vinegar and water. When it reaches a rolling boil, pour it into a bowl and put it in the toaster oven.
After locking the door, let it alone for an hour. After that, clean the toaster oven's interior. Heat and steam ought to have loosened the filth and made it simpler to remove.