Pesach Kashering

I have a variety of metal or partly metal kitchen utensils which are designed to be used for a specific purpose such as: a corkscrew; a melon baller; a lemon / orange zester; a lemon / orange juicer; a vegetable grater; a Vidalia Onion Chopper (also called a Slap Chopper); or metal measuring spoons.  Such utensils either never come in contact with Hametz, or never come in contact with heat sources, or both. Do these utensils need Kashered for Pesach by immersion in boiling water or can they just be cleaned with soap and water? Thank you for all you do. Your efforts are appreciated more than you know.