Q. If you cut an onion with a milchig knife that wasn’t used the last 24 h. and then you cut the same onion with a pareve knife, do you have to kasher the pareve knife? If yes how?

A. Horav Shlomo Miller’s Shlit”a opinion is that it suffices if you just wash the thoroughly previously cleaned knife, with the hot water from the tap, after a twenty-four hour period of not using it.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a