TODAY IS ROSH HODESH NISAN
Sink and countertops: The sink, even when made of porcelain, should be cleaned by pouring on it boiling water. Countertops and kitchen-tables, if possible, it should be poured on them boiling water. If that is not possible they should be thoroughly cleaned or covered in order to use them for Pesaḥ. For a regular table, after it is cleaned, the custom is to use a Pesaḥ or a new tablecloth.
Dishwasher: A day before Pesaḥ, after the dishwasher is completely clean, it has to run on an empty cycle without dishes but with detergent. Then the dishwasher becomes ready for Pesaḥ use. Rabbi Eliyahu Ben-Hayim recommends to replace the dishwasher racks or to use some kind of an added base to cover them, in order to avoid a direct contact of the Pesaḥ utensils with the year round racks. The reason for this stricter stand for the dishwasher is that unlike an oven or a microwave, where only the absorbed vapors need to be eliminated, in the dishwasher, tangible ḥameṣ (ḥameṣ ba'ayin) might be present, which makes its cleaning more difficult.
Oven: The oven should not be used for 24 hours. Then it must go thorough a deep cleaning. Second, if it is a self-cleaning oven, we have to do one self-clean cycle and then it becomes ready forPesaḥ. If it is not a self-cleaning oven, after we thoroughly clean it, we let the oven run on the highest temperature-setting, for an hour, including the racks. Then the oven is Kosher for Pesaḥ.
Microwave: Take a bowl of water, with some detergent or soap in it, and let it boil in the microwave until the microwave walls are filled with its steam. The vapor penetrates the walls rendering the microwave Kosher for Pesaḥ. If you can't do this and you need to use a year-round microwave during Pesaḥ, cover completely the food in a container or Ziploc products, Saran wrap or any other hermetic microwavable (and safe!) covers.