Be sure the cleansing agent reaches into all the cracks and soaks into any crumbs that might be left there. The usual practice is to line the cabinets. Take the food out, and wash it with a rag soaked in a household cleaner. The racks are usually covered. Clean the sinks, and pour a kettle of boiling water into them and on their sides.
Some people pour hot water mixed with bleach down the drain.
Cleaning, without any other kashering procedure, is sufficient. If they were used for hot chometz they should first be cleaned well. Then either boiling hot water should be poured on them, or they should be completely covered so that nothing Pesach dik touches them. Some people do both. Wash them with a household cleaner.