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...

Cutting board

Do plastic cutting boards need to be kashered ? Also, I was wondering if it’s possible to switch my knife I kashered from fleishik to milchik after kashering it for pesach. Thank you!