K’vod haRav, I have a countertop convection toaster oven which is perfectly clean, almost brand-new, rarely used, only to make pareve potato kugel, last used over a year ago. Last week it was used once to make homemade pizza, uncovered, on a sheet of aluminum foil. It is still perfectly clean. To use it again only for uncovered pareve (potato kugel, etc.) do I need to kasher it and if so, how? Thank you.
You should make sure it is perfectly clean and then put in on the highest setting for about 1/2 hour.