A microwave oven that has a browning element cannot be kashered for Pesach. All exposed parts should be thoroughly cleaned. If the parts are not removable, the appliance cannot be kashered. Toaster ovens cannot be kashered. Stainless steel dishwashers can be kashered by running though a complete cycle, cleaning filter at bottom, and replacing racks.
Some authorities maintain that porcelain-lined dishwashers can be kashered in the same way.
Table tops, shelves and pantry or kitchen surfaces that are used during the year should be thoroughly cleaned and scoured before placing Pesach utensils on them. It is highly preferable that all such surfaces be covered during the entire week of Pesach. You can use heavy shelf paper, heavy foil or ornamented plastic cloth to cover all surfaces. Shelves for Pesach dishes should be thoroughly cleaned and covered. Kasher metal sinks by a thorough cleaning and by pouring boiling water over all surfaces.